Start by understanding the Traveling Salesman Problem (TSP) and why a bitmask is used to represent subsets of visited cities.

Recall that in TSP, the goal is to find the shortest possible route that visits each city exactly once and returns to the origin city. The bitmask DP approach tracks visited cities and the current city to avoid recomputation.

Optimize the O(n²·2ⁿ) DP by precomputing distances between cities and ensuring the bitmask transitions correctly update the minimum path cost for each state.