1 '''
2 岛屿的最大面积
3 给定一个包含了一些 0 和 1的非空二维数组 grid , 一个 岛屿 是由四个方向 (水平或垂直) 的 1 (代表土地) 构成的组合。你可以假设二维矩阵的四个边缘都被水包围着。
4 找到给定的二维数组中最大的岛屿面积。(如果没有岛屿，则返回面积为0。)
5 示例 1:
6 [[0,0,1,0,0,0,0,1,0,0,0,0,0],
7 [0,0,0,0,0,0,0,1,1,1,0,0,0],
8 [0,1,1,0,1,0,0,0,0,0,0,0,0],
9 [0,1,0,0,1,1,0,0,1,0,1,0,0],
10 [0,1,0,0,1,1,0,0,1,1,1,0,0],
11 [0,0,0,0,0,0,0,0,0,0,1,0,0],
12 [0,0,0,0,0,0,0,1,1,1,0,0,0],
13 [0,0,0,0,0,0,0,1,1,0,0,0,0]]
14 对于上面这个给定矩阵应返回 6。注意答案不应该是11，因为岛屿只能包含水平或垂直的四个方向的‘1’。
15
16 示例 2:
17 [[0,0,0,0,0,0,0,0]]
18 对于上面这个给定的矩阵, 返回 0。
19 注意: 给定的矩阵grid 的长度和宽度都不超过 50。
20 '''
21
22
23 class Solution:
24 def maxAreaOfIsland(self, grid):
25 """
26 :type grid: List[List[int]]
27 :rtype: int
28 """
29 mx = 0
30 for i in range(len(grid)):
31 for j in range(len(grid[i])):
32 if grid[i][j] == 1:
33 num = self.deepSearch(grid, i, j)
34 mx = max(num, mx)
35 return mx
36
37 def deepSearch(self, g, i, j):
38 g[i][j] = 0
39 x = len(g)
40 y = len(g[0])
41 c = 1
42 if i - 1 >= 0 and g[i - 1][j]: # 上
43 c = c + self.deepSearch(g, i - 1, j)
44 if j + 1 < y and g[i][j + 1]: # 右
45 c = c + self.deepSearch(g, i, j + 1)
46 if i + 1 < x and g[i + 1][j]: # 下
47 c = c + self.deepSearch(g, i + 1, j)
48 if j - 1 >= 0 and g[i][j - 1]: # 左
49 c = c + self.deepSearch(g, i, j - 1)
50 return c
51
52
53 if __name__ == '__main__':
54 grid = [[0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0],
55 [0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0],
56 [0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0],
57 [0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0],
58 [0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0],
59 [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0],
60 [0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0],
61 [0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0]]
62 ret = Solution().maxAreaOfIsland(grid)
63 print(ret)
