| from typing import List | |
| class Solution: | |
| def slidingPuzzle(self, board: List[List[int]]) -> int: | |
| neighbors = { | |
| 0: (1, 3), | |
| 1: (0, 2, 4), | |
| 2: (1, 5), | |
| 3: (0, 4), | |
| 4: (1, 3, 5), | |
| 5: (2, 4), | |
| } | |
| curr = tuple(c for l in board for c in l) | |
| target = (1, 2, 3, 4, 5, 0) | |
| zero_index = curr.index(0) | |
| queue = [(curr, zero_index)] | |
| visited = {curr} | |
| res = -1 | |
| while queue: | |
| res += 1 | |
| l = len(queue) | |
| for i in range(l): | |
| curr, zero_index = queue[i] | |
| if curr == target: | |
| return res | |
| curr_list = list(curr) | |
| for n in neighbors[zero_index]: | |
| curr_list[zero_index], curr_list[n] = curr_list[n], curr_list[zero_index] | |
| new = tuple(curr_list) | |
| if new not in visited: | |
| visited.add(new) | |
| queue.append((new, n)) | |
| curr_list[zero_index], curr_list[n] = curr_list[n], curr_list[zero_index] | |
| queue = queue[l:] | |
| return -1 | |