题解 | #岛屿数量#

import java.util.*;


public class Solution {
    /**
     * 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字符型二维数组 
     * @return int整型
     */
    public int solve (char[][] grid) {
        // write code here
        int count = 0;
        for(int i=0;i<grid.length;i++){
            for(int j=0;j<grid[0].length;j++){
                if(grid[i][j]=='1'){
                    count++;
                    dfs(grid,i,j);
                }
            }
        }
        return count;
    }

    public void dfs(char[][] grid,int i,int j){
        if(i<0 || j<0 || i>=grid.length || j>=grid[0].length){
            return;
        }
        if(grid[i][j] == '1'){
            grid[i][j] = '0';
            dfs(grid,i-1,j);
            dfs(grid,i+1,j);
            dfs(grid,i,j+1);
            dfs(grid,i,j-1);
        }
        return;
    }
}