diff --git a/problems/0130.被围绕的区域.md b/problems/0130.被围绕的区域.md index e244873b..e8a1f02f 100644 --- a/problems/0130.被围绕的区域.md +++ b/problems/0130.被围绕的区域.md @@ -385,6 +385,55 @@ class Solution { } } ``` +### Python3 + +```Python +// 深度优先遍历 +class Solution: + dir_list = [(0, 1), (0, -1), (1, 0), (-1, 0)] + def solve(self, board: List[List[str]]) -> None: + """ + Do not return anything, modify board in-place instead. + """ + row_size = len(board) + column_size = len(board[0]) + visited = [[False] * column_size for _ in range(row_size)] + # 从边缘开始,将边缘相连的O改成A。然后遍历所有,将A改成O,O改成X + # 第一行和最后一行 + for i in range(column_size): + if board[0][i] == "O" and not visited[0][i]: + self.dfs(board, 0, i, visited) + if board[row_size-1][i] == "O" and not visited[row_size-1][i]: + self.dfs(board, row_size-1, i, visited) + + # 第一列和最后一列 + for i in range(1, row_size-1): + if board[i][0] == "O" and not visited[i][0]: + self.dfs(board, i, 0, visited) + if board[i][column_size-1] == "O" and not visited[i][column_size-1]: + self.dfs(board, i, column_size-1, visited) + + for i in range(row_size): + for j in range(column_size): + if board[i][j] == "A": + board[i][j] = "O" + elif board[i][j] == "O": + board[i][j] = "X" + + + def dfs(self, board, x, y, visited): + if visited[x][y] or board[x][y] == "X": + return + visited[x][y] = True + board[x][y] = "A" + for i in range(4): + new_x = x + self.dir_list[i][0] + new_y = y + self.dir_list[i][1] + if new_x >= len(board) or new_y >= len(board[0]) or new_x < 0 or new_y < 0: + continue + self.dfs(board, new_x, new_y, visited) + +```