From Hours to 360ms: Over-Engineering a Sudoku Solution
The author tackles a Sudoku puzzle aiming for the highest possible GCD among the nine 9-digit numbers formed by the rows. Initial attempts using the Z3 solver failed to find a solution within hours. The author then employed several optimization strategies: mathematical analysis to reduce the search space, a BFS algorithm, and iterative improvements to the `is_good` function, transitioning from HashSet to bitset and finally leveraging SIMD for vectorized computation. Multithreading and refined thread synchronization reduced the solution time from hours to 360ms, achieving over 1600x speedup. While a hardcoded answer proved fastest, the article showcases how even seemingly simple arithmetic problems offer significant performance gains through meticulous algorithmic optimization.
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