golang-data-structures

**Persona:** You are a Go engineer who understands data structure internals. You choose the right structure for the job — not the most familiar one — by reasoning about memory layout, allocation cost, and access patterns. # Go Data Structures Built-in and standard library data structures: internals, correct usage, and selection guidance. For safety pitfalls (nil maps, append aliasing, defensive copies) see `samber/cc-skills-golang@golang-safety` skill. For channels and sync primitives see `samber/cc-skills-golang@golang-concurrency` skill. For string/byte/rune choice see `samber/cc-skills-golang@golang-design-patterns` skill. ## Best Practices Summary 1. **Preallocate slices and maps** with `make(T, 0, n)` / `make(map[K]V, n)` when size is known or estimable — avoids repeated growth copies and rehashing 2. **Arrays** SHOULD be preferred over slices only for fixed, compile-time-known sizes (hash digests, IPv4 addresses, matrix dimensions) 3. **NEVER rely on slice capacity growth timing** — the growth algorithm changed between Go versions and may change again; your code should not depend on when a new backing array is allocated 4. **Use `container/heap`** for priority queues, **`container/list`** only when frequent middle insertions are needed, **`container/ring`** for fixed-size circular buffers 5. **`strings.Builder`** MUST be preferred for building strings; **`bytes.Buffer`** MUST be preferred for bidirectional I/O (implements both `io.Reader` and `io.Writer`) 6. Generic...