1 class Solution(object): 2     def __init__(self): 3         self.List = list() 4  5     def bfs(self,R,C,S,V): 6         T = list() 7         while len(S) >0: 8             node = S.pop(0) 9             if node[0]-1>=0 and V[node[0]-1][node[1]] == 0:10                 V[node[0]-1][node[1]] = 111                 T.append([node[0]-1,node[1]])12                 self.List.append([node[0]-1,node[1]])13             if node[0]+1
     
      =0 and V[node[0]][node[1]-1] == 0:18                 V[node[0]][node[1]-1] = 119                 T.append([node[0],node[1]-1])20                 self.List.append([node[0],node[1]-1])21             if node[1]+1
      
       0:26             self.bfs(R,C,T,V)27 28 29 30     def allCellsDistOrder(self, R: int, C: int, r0: int, c0: int) -> 'List[List[int]]':31         stack = list()32         visited = [[0 for col in range(C)] for row in range(R)]33         stack.append([r0,c0])34         visited[r0][c0] = 135         self.List.append([r0,c0])36         self.bfs(R,C,stack,visited)37         return self.List
      
     

典型的BFS算法，每一“层”都比前一层的距离多1，因此按层遍历的顺序，即为所求。