⚡ Optimize unique_rolls with std::unordered_set#5
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Replaces the O(N^2) linear scan in `roll_table::unique_rolls` with an O(1) `std::unordered_set` lookup for situations where `count + start_index > 16`. This reduces overhead for large roll counts while preserving performance for small roll counts. Co-authored-by: perim <436583+perim@users.noreply.github.com>
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💡 What: The optimization implemented replaces the O(N^2) linear scan in
roll_table::unique_rollswith an O(1) amortizedstd::unordered_setlookup. It conditionally executes only for loops with iterations > 16 to avoid the high allocation and hashing overhead ofunordered_setfor smallN.🎯 Why: Previously, large uniqueness checks iterating through thousands of rolls would scale poorly due to iterating over all previously seen values before pushing a new value. The unordered_set provides a safer alternative to direct-mapping
std::vectorapproaches since it handles unbounded and arbitrary indices naturally.📊 Measured Improvement: Baseline vs Optimized performance for generating 500 unique rolls out of a 1000 pool weights table (for 5000 iterations):
The result represents approximately an 11% speed improvement for typical large N cases while avoiding dangerous unchecked memory access and bloated array allocation.
PR created automatically by Jules for task 17182220992993073325 started by @perim