golang-data-structures

Go slice growth involves allocating a new backing array and copying elements when capacity is exceeded, causing hidden allocation costs. Preallocating slice capacity using make avoids repeated memory allocations and copying overhead during iterative appends.

Go maps do not shrink after deletes because internal bucket layout remains allocated for structural stability. To reclaim memory from a shrunken Go map, copy remaining key-value pairs into a newly allocated map to release the old bucket memory.

The best way to build a memory-efficient Go cache is using weak pointers to allow garbage collection of unreferenced cached values. Weak pointers prevent memory leaks in caches by allowing the Go runtime to reclaim memory when no strong references remain.

Use unsafe pointer patterns in Go slices and maps only when bypassing type safety for extreme performance needs, carefully managing aliasing risks. Correct safety patterns dictate preferring standard slices and maps packages over unsafe to avoid pointer aliasing pitfalls.

Choosing between Go slices vs arrays depends on needing dynamic growth versus fixed memory layouts, while heap vs sorting depends on access patterns like continuous retrieval versus batch processing. Selecting the right Go structure requires reasoning about allocation costs and access frequency.