Optimize MessageDifferencer::TreatAsSet time complexity to O(N * K)#28785
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Optimize MessageDifferencer::TreatAsSet time complexity to O(N * K)#28785copybara-service[bot] wants to merge 1 commit into
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Optimizes MessageDifferencer::TreatAsSet() repeated field matching by using hash map lookup (GetRepeatedElementHash) for unmatched elements. Previously, set matching performed O(N^2 * K) element-pair comparisons. With hash map lookup, set matching executes in average O(N * K) time complexity. Updated documentation in message_differencer.h and added TreatAsSet_LargeUnorderedSet test case to message_differencer_unittest.cc. Benchmark Scaling (Old O(N^2) vs. New O(N)): Elements (N) | Old Runtime (ms) | New Runtime (ms) | Speedup ------------ | ---------------- | ---------------- | ------- N = 10 | 0.006 ms | 0.005 ms | 1.2x N = 50 | 0.102 ms | 0.033 ms | 3.1x N = 100 | 0.357 ms | 0.041 ms | 8.8x N = 500 | 8.679 ms | 0.195 ms | 44.5x N = 1,000 | 33.50 ms | 0.387 ms | 86.6x N = 5,000 | 842.48 ms | 1.930 ms | 436.5x N = 10,000 | 3325.82 ms | 3.982 ms | 835.2x speedup PiperOrigin-RevId: 952878430
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Optimize MessageDifferencer::TreatAsSet time complexity to O(N * K)
Optimizes MessageDifferencer::TreatAsSet() repeated field matching by using
hash map lookup (GetRepeatedElementHash) for unmatched elements.
Previously, set matching performed O(N^2 * K) element-pair comparisons. With
hash map lookup, set matching executes in average O(N * K) time complexity.
Updated documentation in message_differencer.h and added
TreatAsSet_LargeUnorderedSet test case to message_differencer_unittest.cc.
Benchmark Scaling (Old O(N^2) vs. New O(N)):