题目要求

思路
1.使用广度优先遍历，将数组中所有为1的元素遍历一遍，遍历过程中使用递归，讲该元素的上下左右四个方向的元素值也置为0
2.统计一共执行过多少次，次数就是岛屿数量
代码实现

class Solution {
public:int solve(vector<vector<char> >& grid) {int n = grid.size();int m = grid[0].size();int index = 0;for(int i = 0; i < n; i++){for(int j = 0; j < m; j++){if(grid[i][j] == '1'){index++;// cout << i << " " << j <<endl;dfs(grid, i, j);}}}return index;}void dfs(vector<vector<char>>& grid, int i, int j){if(grid[i][j] == '1')grid[i][j] = '0';if(i > 0 && grid[i-1][j] == '1')dfs(grid, i-1, j);if(j > 0 && grid[i][j-1] == '1')dfs(grid, i, j-1);if(i < grid.size() - 1 && grid[i+1][j] == '1')dfs(grid, i+1, j);if(j < grid[0].size() - 1 && grid[i][j+1] == '1')dfs(grid, i, j+1);}
};