Leetcode 773. Sliding Puzzle

Given a 2x3 sliding puzzle with tiles 1–5 and a blank (0), find the minimum number of swaps of 0 with its 4-directional neighbors to reach the target [[1,2,3],[4,5,0]] (or return -1 if impossible). This is a shortest-path search in the permutation state graph (solvable via BFS/heuristic search due to the small state space).