题解 | #岛屿数量#

import java.util.*;


public class Solution {
    /**
     * 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) {
        int result = 0;
        for (int i = 0; i < grid.length; i++) {
            for (int j = 0; j < grid[0].length; j++) {
                if (grid[i][j] == '1'){
                    dfs(grid,i,j);
                    result++;
                }
                
            }
        }
        return result;
    }

    public void dfs(char[][] grid, int i, int j){
        if (i<0 || i>=grid.length || j<0 || j>=grid[0].length || grid[i][j] != '1'){
            return;
        }
        grid[i][j] = 2;
        dfs(grid,i+1,j);
        dfs(grid,i-1,j);
        dfs(grid,i,j+1);
        dfs(grid,i,j-1);
    }
}