题解 | 岛屿数量

class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 判断岛屿数量
     * @param grid char字符型vector<vector<>> 
     * @return int整型
     */
                                                                                                                                                   
    
    void dfs(vector<vector<char> >& grid,int i,int j){
        int m,n;
        m = grid.size();
        n = grid[0].size();
        grid[i][j]='0';
        if(i-1>=0 && grid[i-1][j]=='1') dfs(grid,i-1,j);
        if(j-1>=0 && grid[i][j-1]=='1') dfs(grid,i,j-1);
        if(i+1<=m-1 && grid[i+1][j]=='1') dfs(grid,i+1,j);
        if(j+1<=n-1 && grid[i][j+1]=='1') dfs(grid,i,j+1);
    }
    int solve(vector<vector<char> >& grid) {
        // write code here
        if(grid.empty()) return 0;
        int m,n;
        m = grid.size();
        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);}
            }
        }
        return res;
    }
};