diff --git a/applications/test/HashTable2/Test-HashTable2.C b/applications/test/HashTable2/Test-HashTable2.C
index 19406361fc..bcc6913b86 100644
--- a/applications/test/HashTable2/Test-HashTable2.C
+++ b/applications/test/HashTable2/Test-HashTable2.C
@@ -124,11 +124,11 @@ int main(int argc, char *argv[])
         << "toc: " << flatOutput(table0.toc()) << nl;
 
     HashTable<label, label, Hash<label>> table2
-    ({
-        {3, 10},
-        {5, 12},
-        {7, 16}
-    });
+    (
+        // From key/value pairs
+        labelList({3, 5, 7}),
+        labelList({10, 12, 16})
+    );
 
     Info<< "table2: " << table2 << nl
         << "toc: " << flatOutput(table2.toc()) << nl;
diff --git a/applications/test/cstring/Make/files b/applications/test/cstring/Make/files
index eb7e33dc8b..f98b8f1b1a 100644
--- a/applications/test/cstring/Make/files
+++ b/applications/test/cstring/Make/files
@@ -1,3 +1,3 @@
-Test-cstring.C
+Test-cstring.cxx
 
 EXE = $(FOAM_USER_APPBIN)/Test-cstring
diff --git a/applications/test/cstring/Test-cstring.C b/applications/test/cstring/Test-cstring.cxx
similarity index 89%
rename from applications/test/cstring/Test-cstring.C
rename to applications/test/cstring/Test-cstring.cxx
index 095a2253a1..002300e009 100644
--- a/applications/test/cstring/Test-cstring.C
+++ b/applications/test/cstring/Test-cstring.cxx
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2017 OpenCFD Ltd.
+    Copyright (C) 2016-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -81,8 +81,7 @@ int print(char *argv[])
 
 int main(int argc, char *argv[])
 {
-    DynamicList<string> dynlst;
-    dynlst.reserve(16);
+    DynamicList<string> dynlst(16);
 
     dynlst.push_back("string1 with content");
     dynlst.push_back("string2 other content");
@@ -104,6 +103,18 @@ int main(int argc, char *argv[])
         Info<< nl;
     }
 
+    {
+        CStringList inC({ "string1", "string2", "string3", "end" });
+
+        Info<< "null-terminated string list from " << nl;
+        print(inC.strings());
+
+        Info<< "sublist: starting at " << inC.size()/2 << nl;
+        print(inC.strings(inC.size()/2));
+
+        Info<< nl;
+    }
+
     {
         string testInput
         (
@@ -124,7 +135,7 @@ int main(int argc, char *argv[])
         Info<< nl;
     }
 
-    Info<<"command-line with " << CStringList::count(argv) << " items"<< endl;
+    Info<< "command-line with " << CStringList::count(argv) << " items" << nl;
 
     print(argc, argv);
 
diff --git a/applications/utilities/mesh/conversion/gmshToFoam/gmshToFoam.C b/applications/utilities/mesh/conversion/gmshToFoam/gmshToFoam.C
index 77331991ab..b4f6e8d6fe 100644
--- a/applications/utilities/mesh/conversion/gmshToFoam/gmshToFoam.C
+++ b/applications/utilities/mesh/conversion/gmshToFoam/gmshToFoam.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2020-2023 OpenCFD Ltd.
+    Copyright (C) 2020-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -98,19 +98,6 @@ bool skipSection(IFstream& inFile)
 }
 
 
-void renumber
-(
-    const Map<label>& mshToFoam,
-    labelList& labels
-)
-{
-    forAll(labels, labelI)
-    {
-        labels[labelI] = mshToFoam[labels[labelI]];
-    }
-}
-
-
 // Find face in pp which uses all vertices in meshF (in mesh point labels)
 label findFace(const primitivePatch& pp, const labelList& meshF)
 {
@@ -587,7 +574,7 @@ void readCellsLegacy
         {
             lineStr >> triPoints[0] >> triPoints[1] >> triPoints[2];
 
-            renumber(mshToFoam, triPoints);
+            inplaceRenumber(mshToFoam, triPoints);
 
             const auto regFnd = physToPatch.cfind(regPhys);
 
@@ -620,7 +607,7 @@ void readCellsLegacy
                 >> quadPoints[0] >> quadPoints[1] >> quadPoints[2]
                 >> quadPoints[3];
 
-            renumber(mshToFoam, quadPoints);
+            inplaceRenumber(mshToFoam, quadPoints);
 
             const auto regFnd = physToPatch.cfind(regPhys);
 
@@ -662,7 +649,7 @@ void readCellsLegacy
                 >> tetPoints[0] >> tetPoints[1] >> tetPoints[2]
                 >> tetPoints[3];
 
-            renumber(mshToFoam, tetPoints);
+            inplaceRenumber(mshToFoam, tetPoints);
 
             cells[celli++].reset(tet, tetPoints);
 
@@ -683,7 +670,7 @@ void readCellsLegacy
                 >> pyrPoints[0] >> pyrPoints[1] >> pyrPoints[2]
                 >> pyrPoints[3] >> pyrPoints[4];
 
-            renumber(mshToFoam, pyrPoints);
+            inplaceRenumber(mshToFoam, pyrPoints);
 
             cells[celli++].reset(pyr, pyrPoints);
 
@@ -704,7 +691,7 @@ void readCellsLegacy
                 >> prismPoints[0] >> prismPoints[1] >> prismPoints[2]
                 >> prismPoints[3] >> prismPoints[4] >> prismPoints[5];
 
-            renumber(mshToFoam, prismPoints);
+            inplaceRenumber(mshToFoam, prismPoints);
 
             cells[celli].reset(prism, prismPoints);
 
@@ -745,7 +732,7 @@ void readCellsLegacy
                 >> hexPoints[4] >> hexPoints[5]
                 >> hexPoints[6] >> hexPoints[7];
 
-            renumber(mshToFoam, hexPoints);
+            inplaceRenumber(mshToFoam, hexPoints);
 
             cells[celli].reset(hex, hexPoints);
 
@@ -929,7 +916,7 @@ void readCells
                 IStringStream lineStr(line);
                 lineStr >> elemID >> triPoints[0] >> triPoints[1] >> triPoints[2];
 
-                renumber(mshToFoam, triPoints);
+                inplaceRenumber(mshToFoam, triPoints);
 
                 const auto regFnd = physToPatch.cfind(regPhys);
 
@@ -967,7 +954,7 @@ void readCells
                     >> quadPoints[0] >> quadPoints[1] >> quadPoints[2]
                     >> quadPoints[3];
 
-                renumber(mshToFoam, quadPoints);
+                inplaceRenumber(mshToFoam, quadPoints);
 
                 const auto regFnd = physToPatch.cfind(regPhys);
 
@@ -1017,7 +1004,7 @@ void readCells
                     >> tetPoints[0] >> tetPoints[1] >> tetPoints[2]
                     >> tetPoints[3];
 
-                renumber(mshToFoam, tetPoints);
+                inplaceRenumber(mshToFoam, tetPoints);
 
                 cells[celli++].reset(tet, tetPoints);
             }
@@ -1044,7 +1031,7 @@ void readCells
                     >> pyrPoints[0] >> pyrPoints[1] >> pyrPoints[2]
                     >> pyrPoints[3] >> pyrPoints[4];
 
-                renumber(mshToFoam, pyrPoints);
+                inplaceRenumber(mshToFoam, pyrPoints);
 
                 cells[celli++].reset(pyr, pyrPoints);
             }
@@ -1071,7 +1058,7 @@ void readCells
                     >> prismPoints[0] >> prismPoints[1] >> prismPoints[2]
                     >> prismPoints[3] >> prismPoints[4] >> prismPoints[5];
 
-                renumber(mshToFoam, prismPoints);
+                inplaceRenumber(mshToFoam, prismPoints);
 
                 cells[celli].reset(prism, prismPoints);
 
@@ -1118,7 +1105,7 @@ void readCells
                     >> hexPoints[4] >> hexPoints[5]
                     >> hexPoints[6] >> hexPoints[7];
 
-                renumber(mshToFoam, hexPoints);
+                inplaceRenumber(mshToFoam, hexPoints);
 
                 cells[celli].reset(hex, hexPoints);
 
diff --git a/applications/utilities/mesh/conversion/ideasUnvToFoam/ideasUnvToFoam.C b/applications/utilities/mesh/conversion/ideasUnvToFoam/ideasUnvToFoam.C
index 125995083d..2c3ca71f09 100644
--- a/applications/utilities/mesh/conversion/ideasUnvToFoam/ideasUnvToFoam.C
+++ b/applications/utilities/mesh/conversion/ideasUnvToFoam/ideasUnvToFoam.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2021 OpenCFD Ltd.
+    Copyright (C) 2021-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -219,14 +219,14 @@ void readPoints
                 << endl;
         }
 
-        point pt;
         is.getLine(line);
-        pt[0] = readUnvScalar(line.substr(0, 25));
-        pt[1] = readUnvScalar(line.substr(25, 25));
-        pt[2] = readUnvScalar(line.substr(50, 25));
 
-        unvPointID.append(pointi);
-        points.append(pt);
+        unvPointID.push_back(pointi);
+        point& p = points.emplace_back();
+
+        p.x() = readUnvScalar(line.substr(0, 25));
+        p.y() = readUnvScalar(line.substr(25, 25));
+        p.z() = readUnvScalar(line.substr(50, 25));
     }
 
     points.shrink();
@@ -847,7 +847,7 @@ int main(int argc, char *argv[])
 
     labelList own(boundaryFaces.size(), -1);
     labelList nei(boundaryFaces.size(), -1);
-    Map<label> faceToCell[2];
+    Pair<Map<label>> faceToCell;
 
     {
         // Can use face::symmHasher or use sorted indices instead
@@ -996,12 +996,7 @@ int main(int argc, char *argv[])
         labelHashSet alreadyOnBoundary;
 
         // Construct map from boundaryFaceIndices
-        Map<label> boundaryFaceToIndex(boundaryFaceIndices.size());
-
-        forAll(boundaryFaceIndices, i)
-        {
-            boundaryFaceToIndex.insert(boundaryFaceIndices[i], i);
-        }
+        Map<label> boundaryFaceToIndex(invertToMap(boundaryFaceIndices));
 
         forAll(patchFaceVerts, patchi)
         {
@@ -1216,20 +1211,13 @@ int main(int argc, char *argv[])
                 {
                     const label old = oldIndizes[i];
                     label noveau = -1;
-                    label c1 = -1, c2 = -1;
-                    if (faceToCell[0].found(old))
-                    {
-                        c1 = faceToCell[0][old];
-                    }
-                    if (faceToCell[1].found(old))
-                    {
-                        c2 = faceToCell[1][old];
-                    }
+
+                    label c1 = faceToCell[0].lookup(old, -1);
+                    label c2 = faceToCell[1].lookup(old, -1);
+
                     if (c1 < c2)
                     {
-                        label tmp = c1;
-                        c1 = c2;
-                        c2 = tmp;
+                        std::swap(c1, c2);
                     }
                     if (c2 == -1)
                     {
diff --git a/applications/utilities/mesh/conversion/tetgenToFoam/tetgenToFoam.C b/applications/utilities/mesh/conversion/tetgenToFoam/tetgenToFoam.C
index 97c67c26a8..152eb1e8be 100644
--- a/applications/utilities/mesh/conversion/tetgenToFoam/tetgenToFoam.C
+++ b/applications/utilities/mesh/conversion/tetgenToFoam/tetgenToFoam.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2015-2021 OpenCFD Ltd.
+    Copyright (C) 2015-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -197,7 +197,7 @@ int main(int argc, char *argv[])
     //
 
     pointField points(nNodes);
-    Map<label> nodeToPoint(nNodes);
+    Map<label> nodeToPoint(2*nNodes);
 
     {
         labelList pointIndex(nNodes);
@@ -439,23 +439,16 @@ int main(int argc, char *argv[])
 
 
                         // Get Foam patchID and update region->patch table.
-                        label patchi = 0;
+                        label patchi = regionToPatch.lookup(region, -1);
 
-                        const auto patchFind = regionToPatch.cfind(region);
-
-                        if (patchFind.good())
-                        {
-                            patchi = *patchFind;
-                        }
-                        else
+                        if (patchi < 0)
                         {
                             patchi = nPatches;
+                            regionToPatch.insert(region, nPatches++);
 
                             Info<< "Mapping tetgen region " << region
                                 << " to patch "
                                 << patchi << endl;
-
-                            regionToPatch.insert(region, nPatches++);
                         }
 
                         boundaryPatch[facei] = patchi;
diff --git a/applications/utilities/mesh/manipulation/splitMeshRegions/splitMeshRegions.C b/applications/utilities/mesh/manipulation/splitMeshRegions/splitMeshRegions.C
index 4594157462..d2cc137639 100644
--- a/applications/utilities/mesh/manipulation/splitMeshRegions/splitMeshRegions.C
+++ b/applications/utilities/mesh/manipulation/splitMeshRegions/splitMeshRegions.C
@@ -295,9 +295,7 @@ void addToInterface
     else
     {
         // Create new interface of size 1.
-        Map<label> zoneToSize;
-        zoneToSize.insert(zoneID, 1);
-        regionsToSize.insert(interface, zoneToSize);
+        regionsToSize(interface).insert(zoneID, 1);
     }
 }
 
@@ -484,18 +482,10 @@ void getInterfaceSizes
                     zoneName + "_" + name1 + "_to_" + name0
                 );
             }
-            interfaceSizes[nInterfaces] = infoIter();
 
-            if (regionsToInterface.found(e))
-            {
-                regionsToInterface[e].insert(zoneID, nInterfaces);
-            }
-            else
-            {
-                Map<label> zoneAndInterface;
-                zoneAndInterface.insert(zoneID, nInterfaces);
-                regionsToInterface.insert(e, zoneAndInterface);
-            }
+            interfaceSizes[nInterfaces] = infoIter();
+            regionsToInterface(e).insert(zoneID, nInterfaces);
+
             nInterfaces++;
         }
     }
diff --git a/src/OpenFOAM/containers/HashTables/HashTable/HashTable.C b/src/OpenFOAM/containers/HashTables/HashTable/HashTable.C
index f564003f7b..681abd1ea2 100644
--- a/src/OpenFOAM/containers/HashTables/HashTable/HashTable.C
+++ b/src/OpenFOAM/containers/HashTables/HashTable/HashTable.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2017-2023 OpenCFD Ltd.
+    Copyright (C) 2017-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -98,14 +98,38 @@ Foam::HashTable<T, Key, Hash>::HashTable(HashTable<T, Key, Hash>&& rhs) noexcept
 template<class T, class Key, class Hash>
 Foam::HashTable<T, Key, Hash>::HashTable
 (
-    std::initializer_list<std::pair<Key, T>> list
+    std::initializer_list<std::pair<Key, T>> list,
+    const bool overwrite
 )
 :
-    HashTable<T, Key, Hash>(2*list.size())
+    HashTable<T, Key, Hash>()
 {
+    reserve(list.size());
+
     for (const auto& keyval : list)
     {
-        set(keyval.first, keyval.second);
+        this->setEntry(overwrite, keyval.first, keyval.second);
+    }
+}
+
+
+template<class T, class Key, class Hash>
+Foam::HashTable<T, Key, Hash>::HashTable
+(
+    const UList<Key>& keys,
+    const UList<T>& values,
+    const bool overwrite
+)
+:
+    HashTable<T, Key, Hash>()
+{
+    const label len = std::min(keys.size(), values.size());
+
+    reserve(len);
+
+    for (label i = 0; i < len; ++i)
+    {
+        this->setEntry(overwrite, keys[i], values[i]);
     }
 }
 
diff --git a/src/OpenFOAM/containers/HashTables/HashTable/HashTable.H b/src/OpenFOAM/containers/HashTables/HashTable/HashTable.H
index 07ffb7e2f0..e1c88a5384 100644
--- a/src/OpenFOAM/containers/HashTables/HashTable/HashTable.H
+++ b/src/OpenFOAM/containers/HashTables/HashTable/HashTable.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2017-2023 OpenCFD Ltd.
+    Copyright (C) 2017-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -252,9 +252,22 @@ public:
         //- Move construct
         HashTable(this_type&& rhs) noexcept;
 
-        //- Construct from an initializer list
-        //  Duplicate entries are handled by overwriting
-        HashTable(std::initializer_list<std::pair<Key, T>> list);
+        //- Construct from key/value pairs in initializer list
+        //  By default, uses insert not overwrite semantics for duplicates.
+        HashTable
+        (
+            std::initializer_list<std::pair<Key, T>> list,
+            const bool overwrite = false
+        );
+
+        //- Construct from key/value pairs
+        //  By default, uses insert not overwrite semantics for duplicates.
+        HashTable
+        (
+            const UList<Key>& keys,
+            const UList<T>& values,
+            const bool overwrite = false
+        );
 
 
     //- Destructor
diff --git a/src/OpenFOAM/containers/HashTables/Map/Map.H b/src/OpenFOAM/containers/HashTables/Map/Map.H
index 4a318f31ee..a2b91f1746 100644
--- a/src/OpenFOAM/containers/HashTables/Map/Map.H
+++ b/src/OpenFOAM/containers/HashTables/Map/Map.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2017-2023 OpenCFD Ltd.
+    Copyright (C) 2017-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -106,10 +106,27 @@ public:
             parent_type(std::move(map))
         {}
 
-        //- Construct from pairs of values
-        Map(std::initializer_list<std::pair<label, T>> map)
+        //- Construct from key/value pairs in initializer list
+        //  By default, uses insert not overwrite semantics for duplicates.
+        Map
+        (
+            std::initializer_list<std::pair<label, T>> map,
+            const bool overwrite = false
+        )
         :
-            parent_type(map)
+            parent_type(map, overwrite)
+        {}
+
+        //- Construct from key/value pairs
+        //  By default, uses insert not overwrite semantics for duplicates.
+        Map
+        (
+            const UList<label>& keys,
+            const UList<T>& values,
+            const bool overwrite = false
+        )
+        :
+            parent_type(keys, values, overwrite)
         {}
 
 
diff --git a/src/OpenFOAM/containers/Lists/ListOps/ListOps.C b/src/OpenFOAM/containers/Lists/ListOps/ListOps.C
index dd73a69686..d221f20bb5 100644
--- a/src/OpenFOAM/containers/Lists/ListOps/ListOps.C
+++ b/src/OpenFOAM/containers/Lists/ListOps/ListOps.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2015 OpenFOAM Foundation
-    Copyright (C) 2018-2020 OpenCFD Ltd.
+    Copyright (C) 2018-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -110,6 +110,24 @@ Foam::labelList Foam::invert(const bitSet& map)
 }
 
 
+Foam::Map<Foam::label> Foam::invertToMap(const labelUList& values)
+{
+    const label len = values.size();
+
+    Map<label> inverse(2*len);
+
+    for (label i = 0 ; i < len; ++i)
+    {
+        // For correct behaviour with duplicates, do NOT use
+        //    inverse.insert(values[i], inverse.size());
+
+        inverse.insert(values[i], i);
+    }
+
+    return inverse;
+}
+
+
 Foam::labelListList Foam::invertOneToMany
 (
     const label len,
@@ -122,16 +140,26 @@ Foam::labelListList Foam::invertOneToMany
     {
         if (newIdx >= 0)
         {
+            #ifdef FULLDEBUG
+            if (newIdx >= len)
+            {
+                FatalErrorInFunction
+                    << "Inverse location " << newIdx
+                    << " is out of range. List has size " << len
+                    << abort(FatalError);
+            }
+            #endif
+
             ++sizes[newIdx];
         }
     }
 
     labelListList inverse(len);
 
-    for (label i=0; i < len; ++i)
+    for (label i = 0; i < len; ++i)
     {
         inverse[i].resize(sizes[i]);
-        sizes[i] = 0; // reset size counter
+        sizes[i] = 0;  // reset size counter
     }
 
     label i = 0;
@@ -196,7 +224,7 @@ void Foam::inplaceReorder
     const bool prune
 )
 {
-    input = reorder(oldToNew, input, prune);
+    input = Foam::reorder(oldToNew, input, prune);
 }
 
 
diff --git a/src/OpenFOAM/containers/Lists/ListOps/ListOps.H b/src/OpenFOAM/containers/Lists/ListOps/ListOps.H
index b72a3da928..4b5a1f3adf 100644
--- a/src/OpenFOAM/containers/Lists/ListOps/ListOps.H
+++ b/src/OpenFOAM/containers/Lists/ListOps/ListOps.H
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2017-2023 OpenCFD Ltd.
+    Copyright (C) 2017-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -59,16 +59,21 @@ SourceFiles
 namespace Foam
 {
 
-//- Renumber the values (not the indices) of a list.
-//  Negative IntListType elements are left untouched.
+//- Renumber the values within a list.
+//  Negative input values are left untouched.
 template<class IntListType>
 IntListType renumber(const labelUList& oldToNew, const IntListType& input);
 
-//- Inplace renumber the values (not the indices) of a list.
-//  Negative IntListType elements are left untouched.
+//- Inplace renumber the values within a list.
+//  Negative input values are left untouched.
 template<class IntListType>
 void inplaceRenumber(const labelUList& oldToNew, IntListType& input);
 
+//- Inplace renumber the values of a list.
+//  Values that are not mapped by oldToNew are left untouched.
+template<class IntListType>
+void inplaceRenumber(const Map<label>& oldToNew, IntListType& input);
+
 
 //- Reorder the elements of a list.
 //  Locations with negative oldToNew values are left as is (copy-through).
@@ -362,6 +367,14 @@ labelList invert(const label len, const bitSet& map);
 //  \return the inverse mapping with -1 for unmapped elements.
 labelList invert(const bitSet& map);
 
+//- Create inverse mapping, which is a lookup table into the given list
+//  \param values the values (likely unique).
+//
+//  Negative values are allowed, duplicates are "first wins"
+//
+//  \return the inverse lookup
+Map<label> invertToMap(const labelUList& values);
+
 //- Invert one-to-many map. Unmapped elements will be size 0.
 labelListList invertOneToMany(const label len, const labelUList& map);
 
diff --git a/src/OpenFOAM/containers/Lists/ListOps/ListOpsTemplates.C b/src/OpenFOAM/containers/Lists/ListOps/ListOpsTemplates.C
index e1914040e3..4824a41915 100644
--- a/src/OpenFOAM/containers/Lists/ListOps/ListOpsTemplates.C
+++ b/src/OpenFOAM/containers/Lists/ListOps/ListOpsTemplates.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2015-2023 OpenCFD Ltd.
+    Copyright (C) 2015-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -71,6 +71,27 @@ void Foam::inplaceRenumber
 }
 
 
+template<class IntListType>
+void Foam::inplaceRenumber
+(
+    const Map<label>& oldToNew,
+    IntListType& input
+)
+{
+    const label len = input.size();
+
+    for (label i = 0; i < len; ++i)
+    {
+        const auto fnd = oldToNew.cfind(input[i]);
+
+        if (fnd.good())
+        {
+            input[i] = fnd.val();
+        }
+    }
+}
+
+
 template<class ListType>
 ListType Foam::reorder
 (
@@ -224,7 +245,7 @@ void Foam::inplaceReorder
     const bool prune
 )
 {
-    input = reorder(oldToNew, input, prune);
+    input = Foam::reorder(oldToNew, input, prune);
 
     // Verify address (for movable refs)
     // Info<< "now have " << name(input.cdata()) << nl;
diff --git a/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C b/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C
index 6ad4372c6b..e7a6ee9833 100644
--- a/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C
+++ b/src/OpenFOAM/meshes/polyMesh/globalMeshData/globalMeshData.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2015-2023 OpenCFD Ltd.
+    Copyright (C) 2015-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -35,6 +35,7 @@ License
 #include "processorPolyPatch.H"
 #include "processorTopologyNew.H"
 #include "globalIndexAndTransform.H"
+#include "ListOps.H"
 #include "Pstream.H"
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
@@ -314,11 +315,8 @@ void Foam::globalMeshData::calcSharedEdges() const
 
     // Since don't want to construct pointEdges for whole mesh create
     // Map for all shared points.
-    Map<label> meshToShared(2*sharedPtLabels.size());
-    forAll(sharedPtLabels, i)
-    {
-        meshToShared.insert(sharedPtLabels[i], i);
-    }
+    Map<label> meshToShared(invertToMap(sharedPtLabels));
+
 
     // Find edges using shared points. Store correspondence to local edge
     // numbering. Note that multiple local edges can have the same shared
diff --git a/src/OpenFOAM/meshes/polyMesh/syncTools/syncToolsTemplates.C b/src/OpenFOAM/meshes/polyMesh/syncTools/syncToolsTemplates.C
index dbd296f421..874a3726b3 100644
--- a/src/OpenFOAM/meshes/polyMesh/syncTools/syncToolsTemplates.C
+++ b/src/OpenFOAM/meshes/polyMesh/syncTools/syncToolsTemplates.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2015-2023 OpenCFD Ltd.
+    Copyright (C) 2015-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -359,11 +359,7 @@ void Foam::syncTools::syncPointMap
         // pointValues (keyed on mesh points).
 
         // Map from global shared index to meshpoint
-        Map<label> sharedToMeshPoint(2*sharedPtAddr.size());
-        forAll(sharedPtAddr, i)
-        {
-            sharedToMeshPoint.insert(sharedPtAddr[i], sharedPtLabels[i]);
-        }
+        Map<label> sharedToMeshPoint(sharedPtAddr, sharedPtLabels);
 
         forAllConstIters(sharedToMeshPoint, iter)
         {
@@ -622,11 +618,7 @@ void Foam::syncTools::syncEdgeMap
     const labelList& sharedPtLabels = pd.sharedPointLabels();
 
     // 1. Create map from meshPoint to globalShared index.
-    Map<label> meshToShared(2*sharedPtLabels.size());
-    forAll(sharedPtLabels, i)
-    {
-        meshToShared.insert(sharedPtLabels[i], sharedPtAddr[i]);
-    }
+    Map<label> meshToShared(sharedPtLabels, sharedPtAddr);
 
     // Values on shared points. From two sharedPtAddr indices to a value.
     EdgeMap<T> sharedEdgeValues(meshToShared.size());
diff --git a/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchMeshData.C b/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchMeshData.C
index c75900e850..9650ab4138 100644
--- a/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchMeshData.C
+++ b/src/OpenFOAM/meshes/primitiveMesh/PrimitivePatch/PrimitivePatchMeshData.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2015 OpenFOAM Foundation
-    Copyright (C) 2016 OpenCFD Ltd.
+    Copyright (C) 2016-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -129,15 +129,9 @@ Foam::PrimitivePatch<FaceList, PointField>::calcMeshPointMap() const
             << abort(FatalError);
     }
 
-    const labelList& mp = meshPoints();
+    const labelList& meshPts = meshPoints();
 
-    meshPointMapPtr_.reset(new Map<label>(2*mp.size()));
-    auto& mpMap = *meshPointMapPtr_;
-
-    forAll(mp, i)
-    {
-        mpMap.insert(mp[i], i);
-    }
+    meshPointMapPtr_.reset(new Map<label>(invertToMap(meshPts)));
 
     DebugInfo << "Calculated mesh point map" << endl;
 }
diff --git a/src/OpenFOAM/primitives/strings/lists/CStringList.C b/src/OpenFOAM/primitives/strings/lists/CStringList.C
index 88d16f872e..d9edbe829c 100644
--- a/src/OpenFOAM/primitives/strings/lists/CStringList.C
+++ b/src/OpenFOAM/primitives/strings/lists/CStringList.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2017-2022 OpenCFD Ltd.
+    Copyright (C) 2017-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -28,20 +28,67 @@ License
 #include "CStringList.H"
 #include "Ostream.H"
 
+// * * * * * * * * * * * * * * * Member Functions  * * * * * * * * * * * * * //
+
+int Foam::CStringList::reset
+(
+    std::initializer_list<const char* const> input
+)
+{
+    clear();
+
+    if (!input.size())
+    {
+        // Special handling of an empty list
+        argv_ = new char*[1];
+        argv_[0] = nullptr;     // Final nullptr terminator
+        return 0;
+    }
+
+    // Count overall required string length, including each trailing nul char
+    for (const char* const s : input)
+    {
+        // nbytes_ += Foam::string::length(s) + 1
+        nbytes_ += (s ? strlen(s) : 0) + 1;
+    }
+    --nbytes_;  // Do not include final nul char in overall count
+
+    argv_ = new char*[input.size()+1];  // Extra +1 for terminating nullptr
+    data_ = new char[nbytes_+1];        // Extra +1 for terminating nul char
+
+    argv_[0] = data_;   // Starts here
+
+    for (const char* const s : input)
+    {
+        char *next = stringCopy(argv_[argc_], s);
+        argv_[++argc_] = next;  // The start of next string
+    }
+
+    argv_[argc_] = nullptr;     // Final nullptr terminator
+
+    return argc_;
+}
+
+
+
 // * * * * * * * * * * * * * * * IOstream Operators  * * * * * * * * * * * * //
 
 Foam::Ostream& Foam::operator<<(Ostream& os, const CStringList& list)
 {
     const int n = list.size();
 
-    for (int i = 0, space = 0; i < n; ++i)
+    bool separator = false;
+
+    for (int i = 0; i < n; ++i)
     {
         const char* p = list.get(i);
 
         if (p && *p)
         {
-            if (space++) os << ' ';
+            if (separator) os << ' ';
             os << p;
+
+            separator = true;
         }
     }
 
diff --git a/src/OpenFOAM/primitives/strings/lists/CStringList.H b/src/OpenFOAM/primitives/strings/lists/CStringList.H
index e562ad2052..ec9b173675 100644
--- a/src/OpenFOAM/primitives/strings/lists/CStringList.H
+++ b/src/OpenFOAM/primitives/strings/lists/CStringList.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2022 OpenCFD Ltd.
+    Copyright (C) 2016-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -55,6 +55,9 @@ Description
 #include "stringList.H"
 #include "wordList.H"
 
+#include <algorithm>  // std::copy
+#include <utility>    // std::initializer_list
+
 // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
 
 namespace Foam
@@ -87,6 +90,11 @@ class CStringList
 
     // Private Member Functions
 
+        //- Copy characters into dest as NUL-terminated string.
+        //
+        //  \return location one-past end of dest (ie, the next destination)
+        static inline char* stringCopy(char* dest, const char* src);
+
         //- Copy string characters into dest as NUL-terminated string.
         //  Forces conversion of std::sub_match to string form
         //
@@ -99,6 +107,10 @@ class CStringList
         int resetContent(const ListType& input);
 
 
+public:
+
+    // Generated Methods
+
         //- No copy construct
         CStringList(const CStringList&) = delete;
 
@@ -106,13 +118,18 @@ class CStringList
         void operator=(const CStringList&) = delete;
 
 
-public:
-
     // Constructors
 
         //- Default construct, adding content later (via reset).
         inline constexpr CStringList() noexcept;
 
+        //- Copy construct from a list of C-strings
+        //  Copies the input characters.
+        inline explicit CStringList
+        (
+            std::initializer_list<const char* const> input
+        );
+
         //- Copy construct from a list of strings
         //  Copies the input characters.
         template<class StringType>
@@ -174,6 +191,10 @@ public:
         //- Clear contents and free memory
         inline void clear();
 
+        //- Copy the input list of C-strings
+        //  \return number of arguments (argc)
+        int reset(std::initializer_list<const char* const> input);
+
         //- Copy the input list of strings.
         //  \return number of arguments (argc)
         template<class StringType>
diff --git a/src/OpenFOAM/primitives/strings/lists/CStringListI.H b/src/OpenFOAM/primitives/strings/lists/CStringListI.H
index f7fa66ac08..112a3791dc 100644
--- a/src/OpenFOAM/primitives/strings/lists/CStringListI.H
+++ b/src/OpenFOAM/primitives/strings/lists/CStringListI.H
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2017 OpenCFD Ltd.
+    Copyright (C) 2016-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -27,17 +27,18 @@ License
 
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
 
+inline char* Foam::CStringList::stringCopy(char* dest, const char* src)
+{
+    dest = std::copy_n(src, (src ? strlen(src) : 0), dest);
+    *(dest++) = '\0';
+    return dest;
+}
+
+
 inline char* Foam::CStringList::stringCopy(char *dest, const std::string& src)
 {
-    // Like string::copy() but without extra checks
-    const size_t len = src.length();
-    for (size_t i = 0; i < len; ++i)
-    {
-        *dest = src[i];
-        ++dest;
-    }
+    dest = std::copy_n(src.data(), src.size(), dest);
     *(dest++) = '\0';
-
     return dest;
 }
 
@@ -69,6 +70,17 @@ inline constexpr Foam::CStringList::CStringList() noexcept
 {}
 
 
+inline Foam::CStringList::CStringList
+(
+    std::initializer_list<const char* const> input
+)
+:
+    CStringList()
+{
+    reset(input);
+}
+
+
 template<class StringType>
 inline Foam::CStringList::CStringList(const UList<StringType>& input)
 :
diff --git a/src/OpenFOAM/primitives/strings/lists/CStringListTemplates.C b/src/OpenFOAM/primitives/strings/lists/CStringListTemplates.C
index 9d52052659..69a1d717d2 100644
--- a/src/OpenFOAM/primitives/strings/lists/CStringListTemplates.C
+++ b/src/OpenFOAM/primitives/strings/lists/CStringListTemplates.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2016-2017 OpenCFD Ltd.
+    Copyright (C) 2016-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -34,7 +34,7 @@ int Foam::CStringList::resetContent(const ListType& input)
 {
     clear();
 
-    if (input.empty())
+    if (!input.size())
     {
         // Special handling of an empty list
         argv_ = new char*[1];
@@ -43,9 +43,9 @@ int Foam::CStringList::resetContent(const ListType& input)
     }
 
     // Count overall required string length, including each trailing nul char
-    for (const auto& str : input)
+    for (const auto& s : input)
     {
-        nbytes_ += str.length() + 1;
+        nbytes_ += s.length() + 1;
     }
     --nbytes_;  // Do not include final nul char in overall count
 
@@ -54,10 +54,10 @@ int Foam::CStringList::resetContent(const ListType& input)
 
     argv_[0] = data_;   // Starts here
 
-    for (const auto& str : input)
+    for (const auto& s : input)
     {
-        char *next = stringCopy(argv_[argc_], str);
-        argv_[++argc_] = next;   // The start of next string
+        char *next = stringCopy(argv_[argc_], s);
+        argv_[++argc_] = next;  // The start of next string
     }
 
     argv_[argc_] = nullptr;     // Final nullptr terminator
@@ -76,7 +76,7 @@ Foam::CStringList::asList(int argc, const char * const argv[])
 
     for (int i=0; i < argc; ++i)
     {
-        list[i] = argv[i];
+        if (argv[i]) list[i] = argv[i];
     }
 
     return list;
diff --git a/src/dynamicMesh/attachDetach/detachInterface.C b/src/dynamicMesh/attachDetach/detachInterface.C
index 34f94d4cad..5e3fd103bc 100644
--- a/src/dynamicMesh/attachDetach/detachInterface.C
+++ b/src/dynamicMesh/attachDetach/detachInterface.C
@@ -366,16 +366,8 @@ void Foam::attachDetach::detachInterface
     }
 
     // Create the master layer point map
-    Map<label> masterLayerPointMap(2*mp.size());
+    Map<label> masterLayerPointMap(mp, addedPoints);
 
-    forAll(mp, pointi)
-    {
-        masterLayerPointMap.insert
-        (
-            mp[pointi],
-            addedPoints[pointi]
-        );
-    }
 
     // Grab the list of faces of the master layer
     const labelList masterCellFaces = masterCellFaceMap.toc();
diff --git a/src/dynamicMesh/layerAdditionRemoval/addCellLayer.C b/src/dynamicMesh/layerAdditionRemoval/addCellLayer.C
index 43f12a7cd7..b7e7c1b488 100644
--- a/src/dynamicMesh/layerAdditionRemoval/addCellLayer.C
+++ b/src/dynamicMesh/layerAdditionRemoval/addCellLayer.C
@@ -562,16 +562,8 @@ void Foam::layerAdditionRemoval::addCellLayer
     }
 
     // Create the master layer point map
-    Map<label> masterLayerPointMap(2*mp.size());
+    Map<label> masterLayerPointMap(mp, addedPoints);
 
-    forAll(mp, pointi)
-    {
-        masterLayerPointMap.insert
-        (
-            mp[pointi],
-            addedPoints[pointi]
-        );
-    }
 
     // Grab the list of faces of the master layer
     const labelList masterCellFaces = masterCellFaceMap.toc();
diff --git a/src/dynamicMesh/layerAdditionRemoval/removeCellLayer.C b/src/dynamicMesh/layerAdditionRemoval/removeCellLayer.C
index e04075d2e0..34d8c13ae5 100644
--- a/src/dynamicMesh/layerAdditionRemoval/removeCellLayer.C
+++ b/src/dynamicMesh/layerAdditionRemoval/removeCellLayer.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2018-2022 OpenCFD Ltd.
+    Copyright (C) 2018-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -155,9 +155,9 @@ void Foam::layerAdditionRemoval::removeCellLayer
     }
 
     // Remove all points that will be collapsed
-    forAll(ptc, pointi)
+    for (const label pointi : ptc)
     {
-        ref.setAction(polyRemovePoint(ptc[pointi]));
+        ref.setAction(polyRemovePoint(pointi));
     }
 
     // Grab all faces coming off points to be deleted.  If the face
@@ -167,15 +167,10 @@ void Foam::layerAdditionRemoval::removeCellLayer
     // Make a map of all point to be removed, giving the master point label
     // for each of them
 
-    Map<label> removedPointMap(2*ptc.size());
-
     const labelList& meshPoints =
-        mesh.faceZones()[faceZoneID_.index()]().meshPoints();
+        mesh.faceZones()[faceZoneID_.index()].patch().meshPoints();
 
-    forAll(ptc, pointi)
-    {
-        removedPointMap.insert(ptc[pointi], meshPoints[pointi]);
-    }
+    Map<label> removedPointMap(ptc, meshPoints);
 
     const labelListList& pf = mesh.pointFaces();
 
diff --git a/src/dynamicMesh/meshCut/meshModifiers/multiDirRefinement/multiDirRefinement.C b/src/dynamicMesh/meshCut/meshModifiers/multiDirRefinement/multiDirRefinement.C
index 94b23d800e..497c722219 100644
--- a/src/dynamicMesh/meshCut/meshModifiers/multiDirRefinement/multiDirRefinement.C
+++ b/src/dynamicMesh/meshCut/meshModifiers/multiDirRefinement/multiDirRefinement.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2015-2022 OpenCFD Ltd.
+    Copyright (C) 2015-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -277,16 +277,14 @@ void Foam::multiDirRefinement::refineHex8
     {
         // Create count 1 for original cells
         Map<label> hexCellSet(2*hexCells.size());
-        forAll(hexCells, i)
+        for (const label celli : hexCells)
         {
-            hexCellSet.insert(hexCells[i], 1);
+            hexCellSet.insert(celli, 1);
         }
 
         // Increment count
-        forAll(consistentCells, i)
+        for (const label celli : consistentCells)
         {
-            const label celli = consistentCells[i];
-
             auto iter = hexCellSet.find(celli);
 
             if (iter.good())
diff --git a/src/dynamicMesh/slidingInterface/enrichedPatch/enrichedPatch.C b/src/dynamicMesh/slidingInterface/enrichedPatch/enrichedPatch.C
index e3b7833bbd..05e9d45beb 100644
--- a/src/dynamicMesh/slidingInterface/enrichedPatch/enrichedPatch.C
+++ b/src/dynamicMesh/slidingInterface/enrichedPatch/enrichedPatch.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2017-2020 OpenCFD Ltd.
+    Copyright (C) 2017-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -29,6 +29,7 @@ License
 #include "enrichedPatch.H"
 #include "OFstream.H"
 #include "meshTools.H"
+#include "ListOps.H"
 
 // * * * * * * * * * * * * * * Static Data Members * * * * * * * * * * * * * //
 
@@ -65,12 +66,8 @@ void Foam::enrichedPatch::calcLocalFaces() const
     // Invert mesh points and renumber faces using it
     const labelList& mp = meshPoints();
 
-    Map<label> mpLookup(2*mp.size());
+    Map<label> mpLookup(invertToMap(mp));
 
-    forAll(mp, mpi)
-    {
-        mpLookup.insert(mp[mpi], mpi);
-    }
 
     // Create local faces.
     // Copy original faces and overwrite vertices after
@@ -82,10 +79,7 @@ void Foam::enrichedPatch::calcLocalFaces() const
 
     for (face& f : locFaces)
     {
-        for (label& pointi : f)
-        {
-            pointi = *(mpLookup.cfind(pointi));
-        }
+        inplaceRenumber(mpLookup, f);
     }
 }
 
diff --git a/src/finiteArea/faMesh/faMeshPatches.C b/src/finiteArea/faMesh/faMeshPatches.C
index 6cf01d2a62..11b2ee01e7 100644
--- a/src/finiteArea/faMesh/faMeshPatches.C
+++ b/src/finiteArea/faMesh/faMeshPatches.C
@@ -528,8 +528,9 @@ Foam::faPatchList Foam::faMesh::createPatchList
     }
 
     // Create processor-processor definitions
-    Map<label> procToDefLookup(2*procConnections.size());
+    Map<label> procToDefLookup;
     {
+        procToDefLookup.reserve(procConnections.size());
         faPatchDefs.reserve(faPatchDefs.size() + procConnections.size());
 
         for (const label otherProci : procConnections.sortedToc())
diff --git a/src/finiteVolume/fvMesh/fvMeshSubset/fvMeshSubsetTemplates.C b/src/finiteVolume/fvMesh/fvMeshSubset/fvMeshSubsetTemplates.C
index 233090cd71..7936eaeb1a 100644
--- a/src/finiteVolume/fvMesh/fvMeshSubset/fvMeshSubsetTemplates.C
+++ b/src/finiteVolume/fvMesh/fvMeshSubset/fvMeshSubsetTemplates.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2019-2020 OpenCFD Ltd.
+    Copyright (C) 2019-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -493,11 +493,8 @@ Foam::fvMeshSubset::interpolate
             const labelList& meshPoints = basePatch.meshPoints();
 
             // Make addressing from mesh to patch point
-            Map<label> meshPointMap(2*meshPoints.size());
-            forAll(meshPoints, localI)
-            {
-                meshPointMap.insert(meshPoints[localI], localI);
-            }
+            Map<label> meshPointMap(invertToMap(meshPoints));
+
 
             // Find which subpatch points originate from which patch point
             const pointPatch& subPatch = sMesh.boundary()[patchi];
@@ -515,7 +512,7 @@ Foam::fvMeshSubset::interpolate
 
                 if (iter.good())
                 {
-                    directAddressing[localI] = *iter;
+                    directAddressing[localI] = iter.val();
                 }
             }
 
diff --git a/src/finiteVolume/interpolation/interpolation/interpolationPointMVC/pointMVCWeight.C b/src/finiteVolume/interpolation/interpolation/interpolationPointMVC/pointMVCWeight.C
index 28559e3ded..e26f61466b 100644
--- a/src/finiteVolume/interpolation/interpolation/interpolationPointMVC/pointMVCWeight.C
+++ b/src/finiteVolume/interpolation/interpolation/interpolationPointMVC/pointMVCWeight.C
@@ -254,11 +254,7 @@ Foam::pointMVCWeight::pointMVCWeight
 {
     // Addressing - face vertices to local points and vice versa
     const labelList& toGlobal = mesh.cellPoints()[cellIndex_];
-    Map<label> toLocal(2*toGlobal.size());
-    forAll(toGlobal, i)
-    {
-        toLocal.insert(toGlobal[i], i);
-    }
+    Map<label> toLocal(invertToMap(toGlobal));
 
 
     // Initialise weights
diff --git a/src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C b/src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C
index 93281ea440..130845c196 100644
--- a/src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C
+++ b/src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2015-2023 OpenCFD Ltd.
+    Copyright (C) 2015-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -1364,11 +1364,7 @@ Foam::label Foam::meshRefinement::splitFacesUndo
         }
 
         {
-            Map<label> splitFaceToIndex(2*splitFaces.size());
-            forAll(splitFaces, i)
-            {
-                splitFaceToIndex.insert(splitFaces[i], i);
-            }
+            Map<label> splitFaceToIndex(invertToMap(splitFaces));
 
             forAll(map.faceMap(), facei)
             {
diff --git a/src/meshTools/edgeMesh/edgeFormats/nastran/NASedgeFormat.C b/src/meshTools/edgeMesh/edgeFormats/nastran/NASedgeFormat.C
index 9940ccf093..916d898cd6 100644
--- a/src/meshTools/edgeMesh/edgeFormats/nastran/NASedgeFormat.C
+++ b/src/meshTools/edgeMesh/edgeFormats/nastran/NASedgeFormat.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2017 OpenCFD Ltd.
+    Copyright (C) 2017-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -165,15 +165,8 @@ bool Foam::fileFormats::NASedgeFormat::read
     // transfer to normal lists
     storedPoints().transfer(dynPoints);
 
-    pointId.shrink();
-    dynEdges.shrink();
-
     // Build inverse mapping (NASTRAN pointId -> index)
-    Map<label> mapPointId(2*pointId.size());
-    forAll(pointId, i)
-    {
-        mapPointId.insert(pointId[i], i);
-    }
+    Map<label> mapPointId(invertToMap(pointId));
 
     // note which points were really used and which can be culled
     bitSet usedPoints(points().size());
diff --git a/src/meshTools/edgeMesh/edgeFormats/starcd/STARCDedgeFormat.C b/src/meshTools/edgeMesh/edgeFormats/starcd/STARCDedgeFormat.C
index 9dda97df8b..bab726a6b3 100644
--- a/src/meshTools/edgeMesh/edgeFormats/starcd/STARCDedgeFormat.C
+++ b/src/meshTools/edgeMesh/edgeFormats/starcd/STARCDedgeFormat.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2016-2022 OpenCFD Ltd.
+    Copyright (C) 2016-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -128,11 +128,7 @@ bool Foam::fileFormats::STARCDedgeFormat::read
     );
 
     // Build inverse mapping (STARCD pointId -> index)
-    Map<label> mapPointId(2*pointId.size());
-    forAll(pointId, i)
-    {
-        mapPointId.insert(pointId[i], i);
-    }
+    Map<label> mapPointId(invertToMap(pointId));
     pointId.clear();
 
     // Note which points were really used and which can be culled
diff --git a/src/meshTools/regionSplit2D/regionSplit2D.C b/src/meshTools/regionSplit2D/regionSplit2D.C
index 6d7271e401..c86761302a 100644
--- a/src/meshTools/regionSplit2D/regionSplit2D.C
+++ b/src/meshTools/regionSplit2D/regionSplit2D.C
@@ -130,12 +130,15 @@ Foam::regionSplit2D::regionSplit2D
     }
 
     // In-place renumber the local regionI to global (compact) regionI
-    globalIndex giCompact(compactRegionI);
-    forAllIters(regionToCompactAddr, iter)
     {
-        *iter = giCompact.toGlobal(*iter);
+        const label myProcOffset = globalIndex::calcOffset(compactRegionI);
+        forAllIters(regionToCompactAddr, iter)
+        {
+            iter.val() += myProcOffset;
+        }
     }
 
+
     // Ensure regionToCompactAddr consistent across all processors
     // - not concerned about the op (keys are unique)
     // - map size will be the number of regions in the set of faces
diff --git a/src/meshTools/topoSet/topoSets/faceZoneSet.C b/src/meshTools/topoSet/topoSets/faceZoneSet.C
index e36ba9e404..ab86d89c63 100644
--- a/src/meshTools/topoSet/topoSets/faceZoneSet.C
+++ b/src/meshTools/topoSet/topoSets/faceZoneSet.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2017 OpenFOAM Foundation
-    Copyright (C) 2018-2022,2024 OpenCFD Ltd.
+    Copyright (C) 2018-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -32,6 +32,7 @@ License
 #include "setToFaceZone.H"
 #include "setsToFaceZone.H"
 #include "syncTools.H"
+#include "ListOps.H"
 
 #include "addToRunTimeSelectionTable.H"
 
@@ -177,11 +178,7 @@ void Foam::faceZoneSet::subset(const topoSet& set)
     DynamicList<label> newAddressing(addressing_.size());
     DynamicList<bool> newFlipMap(flipMap_.size());
 
-    Map<label> faceToIndex(addressing_.size());
-    forAll(addressing_, i)
-    {
-        faceToIndex.insert(addressing_[i], i);
-    }
+    Map<label> faceToIndex(invertToMap(addressing_));
 
     const faceZoneSet& zoneSet = refCast<const faceZoneSet>(set);
 
@@ -225,11 +222,7 @@ void Foam::faceZoneSet::addSet(const topoSet& set)
     DynamicList<label> newAddressing(addressing_);
     DynamicList<bool> newFlipMap(flipMap_);
 
-    Map<label> faceToIndex(addressing_.size());
-    forAll(addressing_, i)
-    {
-        faceToIndex.insert(addressing_[i], i);
-    }
+    Map<label> faceToIndex(invertToMap(addressing_));
 
     const faceZoneSet& zoneSet = refCast<const faceZoneSet>(set);
 
@@ -277,11 +270,7 @@ void Foam::faceZoneSet::subtractSet(const topoSet& set)
 
     const faceZoneSet& zoneSet = refCast<const faceZoneSet>(set);
 
-    Map<label> faceToIndex(zoneSet.addressing().size());
-    forAll(zoneSet.addressing(), i)
-    {
-        faceToIndex.insert(zoneSet.addressing()[i], i);
-    }
+    Map<label> faceToIndex(invertToMap(zoneSet.addressing()));
 
     forAll(addressing_, i)
     {
diff --git a/src/parallel/decompose/faDecompose/faMeshDecomposition.C b/src/parallel/decompose/faDecompose/faMeshDecomposition.C
index a3775f461b..6cc52b74ec 100644
--- a/src/parallel/decompose/faDecompose/faMeshDecomposition.C
+++ b/src/parallel/decompose/faDecompose/faMeshDecomposition.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2016-2017 Wikki Ltd
-    Copyright (C) 2018-2022 OpenCFD Ltd.
+    Copyright (C) 2018-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -35,6 +35,7 @@ License
 #include "OSspecific.H"
 #include "Map.H"
 #include "SLList.H"
+#include "ListOps.H"
 #include "globalMeshData.H"
 
 // * * * * * * * * * * * * * Private Member Functions  * * * * * * * * * * * //
@@ -275,17 +276,9 @@ void Foam::faMeshDecomposition::decomposeMesh()
             ioAddr.rename("faceProcAddressing");
             labelIOList fvFaceProcAddressing(ioAddr);
 
-            fvFaceProcAddressingHash.reserve(fvFaceProcAddressing.size());
+            fvFaceProcAddressingHash = invertToMap(fvFaceProcAddressing);
+        }
 
-            forAll(fvFaceProcAddressing, facei)
-            {
-                 fvFaceProcAddressingHash.insert
-                 (
-                     fvFaceProcAddressing[facei],
-                     facei
-                 );
-            }
-        };
 
         const labelList& curProcFaceAddressing = procFaceAddressing_[procI];
 
@@ -1116,12 +1109,8 @@ bool Foam::faMeshDecomposition::writeDecomposition()
     Info<< "\nConstructing processor FA meshes" << endl;
 
     // Make a lookup map for globally shared points
-    Map<label> sharedPointLookup(2*globallySharedPoints_.size());
+    Map<label> sharedPointLookup(invertToMap(globallySharedPoints_));
 
-    forAll(globallySharedPoints_, pointi)
-    {
-        sharedPointLookup.insert(globallySharedPoints_[pointi], pointi);
-    }
 
     label maxProcFaces = 0;
     label totProcFaces = 0;
diff --git a/src/surfMesh/surfaceFormats/abaqus/ABAQUSsurfaceFormat.C b/src/surfMesh/surfaceFormats/abaqus/ABAQUSsurfaceFormat.C
index 849c920a9f..a58d42cbc2 100644
--- a/src/surfMesh/surfaceFormats/abaqus/ABAQUSsurfaceFormat.C
+++ b/src/surfMesh/surfaceFormats/abaqus/ABAQUSsurfaceFormat.C
@@ -5,7 +5,7 @@
     \\  /    A nd           | www.openfoam.com
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
-    Copyright (C) 2020-2022 OpenCFD Ltd.
+    Copyright (C) 2020-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -177,18 +177,13 @@ bool Foam::fileFormats::ABAQUSsurfaceFormat<Face>::read
     // Extra safety
     if (newToOldZone.empty())
     {
-        newToOldZone.resize(1, Zero);
-    }
-
-    Map<label> oldToNewZone(2*newToOldZone.size());
-
-    forAll(newToOldZone, zonei)
-    {
-        oldToNewZone.set(newToOldZone[zonei], zonei);
+        newToOldZone.push_back(0);
     }
 
     wordList  zoneNames(newToOldZone.size());
-    labelList zoneSizes(newToOldZone.size(), Zero);
+    labelList zoneSizes(newToOldZone.size(), Foam::zero{});
+
+    Map<label> oldToNewZone(invertToMap(newToOldZone));
 
     forAllConstIters(reader.elsetMap_, iter)
     {
diff --git a/src/surfMesh/surfaceFormats/nas/NASsurfaceFormat.C b/src/surfMesh/surfaceFormats/nas/NASsurfaceFormat.C
index fedf3f303d..816433decc 100644
--- a/src/surfMesh/surfaceFormats/nas/NASsurfaceFormat.C
+++ b/src/surfMesh/surfaceFormats/nas/NASsurfaceFormat.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2015 OpenFOAM Foundation
-    Copyright (C) 2017-2023 OpenCFD Ltd.
+    Copyright (C) 2017-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -493,16 +493,11 @@ bool Foam::fileFormats::NASsurfaceFormat<Face>::read
     // Transfer to normal lists
     this->storedPoints().transfer(dynPoints);
 
-    pointId.shrink();
     dynFaces.shrink();
 
     // Build inverse mapping (NASTRAN pointId -> index)
-    Map<label> mapPointId;
-    mapPointId.reserve(pointId.size());
-    for (const label pointi : pointId)
-    {
-        mapPointId.insert(pointi, mapPointId.size());
-    }
+    Map<label> mapPointId(invertToMap(pointId));
+    pointId.clearStorage();
 
     // Relabel faces
     // ~~~~~~~~~~~~~
@@ -513,7 +508,6 @@ bool Foam::fileFormats::NASsurfaceFormat<Face>::read
             vert = mapPointId[vert];
         }
     }
-    pointId.clearStorage();
     mapPointId.clear();
 
     DebugInfo
diff --git a/src/surfMesh/surfaceFormats/starcd/STARCDsurfaceFormat.C b/src/surfMesh/surfaceFormats/starcd/STARCDsurfaceFormat.C
index 9c0ae4d633..4b761f239b 100644
--- a/src/surfMesh/surfaceFormats/starcd/STARCDsurfaceFormat.C
+++ b/src/surfMesh/surfaceFormats/starcd/STARCDsurfaceFormat.C
@@ -6,7 +6,7 @@
      \\/     M anipulation  |
 -------------------------------------------------------------------------------
     Copyright (C) 2011-2016 OpenFOAM Foundation
-    Copyright (C) 2016-2022 OpenCFD Ltd.
+    Copyright (C) 2016-2024 OpenCFD Ltd.
 -------------------------------------------------------------------------------
 License
     This file is part of OpenFOAM.
@@ -107,11 +107,7 @@ bool Foam::fileFormats::STARCDsurfaceFormat<Face>::read
     );
 
     // Build inverse mapping (STARCD pointId -> index)
-    Map<label> mapPointId(2*pointId.size());
-    forAll(pointId, i)
-    {
-        mapPointId.insert(pointId[i], i);
-    }
+    Map<label> mapPointId(invertToMap(pointId));
     pointId.clear();