<skill_overview> Keep Rust code fast while staying idiomatic

Optimizing hot loops Reducing allocations Choosing data structures Measuring performance impact

The Rust Book - Performance

</skill_overview> <zero_cost_abstractions>

Use iterators and closures freely; they compile to efficient code Prefer expressive, safe code and measure before micro-optimizing

</zero_cost_abstractions>

Prefer borrowing (&str, &[T]) over allocating (String, Vec) Pre-allocate with Vec::with_capacity when size is known Avoid unnecessary clones; pass references where possible

let mut buf = Vec::with_capacity(1024);

<hot_paths>

Avoid repeated formatting or allocation in tight loops Reuse buffers and temporary values when possible

</hot_paths>

Benchmark with realistic data sizes Compare before and after changes

<anti_patterns> Optimizing before profiling Cloning on each iteration Growing collections without bounds </anti_patterns>