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The STL from the Inside · 3:17
Choosing a Container
Why the vector is the default: its elements share cache lines while a list's nodes are scattered across the heap. We race them on a Mac (summing, and inserting in sorted order, where the list should win and doesn't), compare a map's red-black tree with an unordered_map's hash table, and remove a hidden allocation from string lookups with the transparent comparator std::less<>.
You will learn
- Explain why contiguous storage beats node-based containers on modern caches
- Predict the outcome of vector vs list for traversal and small-element insertion
- Choose between map and unordered_map, and know what each requires of its key
- Use std::less<> to avoid temporary strings in map lookups, and contains() to test membership