题解 | #岛屿数量#

class Solution {
public:
    /**
     * 判断岛屿数量
     * @param grid char字符型vector<vector<>> 
     * @return int整型
     */
    int solve(vector<vector<char> >& grid) {
        // write code here
        int m = grid.size();
        int n = grid[0].size();
        int res = 0;
        for(int i=0; i<m; i++){
            for(int j=0; j<n; j++){
                if(grid[i][j] == '1'){
                    res++;
                    dfs(grid, i, j, m, n);
                }
            }
        }
        return res;
    }
    
    void dfs(vector<vector<char>>& grid, int i, int j, int m, int n){
        if(i<0 || i>=m || j<0 || j>=n){
            return;
        }
        if(grid[i][j] == '0'){
            return;
        }
        
        grid[i][j] = '0';
        dfs(grid, i-1, j, m, n);
        dfs(grid, i+1, j, m, n);
        dfs(grid, i, j-1, m, n);
        dfs(grid, i, j+1, m, n);
    }
    
};