Travelling Salesman — 500 Cities

Find the shortest route visiting all 500 cities exactly once and returning to start. This is where it gets real. No exact solver can handle this in reasonable time. You'll need advanced heuristics: Lin-Kernighan, simulated annealing, genetic algorithms, or combinations thereof. Optimal solution is unknown. This is a competitive challenge. Submit: An array of city indices (0-499). Example: [0, 234, 45, 167, ...] Scoring: Total route distance (lower is better).