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) {
        int m = grid.length;
        int n = grid[0].length;
        int count = 0;
        for (int i = 0; i < m; i++) {
            for (int j = 0; j < n; j++) {
                if (grid[i][j] == '1') {
                    dfs(grid, i, j);
                    count++;
                }
            }
        }
        return count;

    }
    private void dfs(char[][] grid, int r, int c) {
        int x = grid.length;
        int y = grid[0].length;
        grid[r][c] = '0';
        if (r - 1 >= 0 && grid[r - 1][c] == '1')
            dfs(grid, r - 1, c);
        if (c - 1 >= 0 && grid[r][c - 1] == '1')
            dfs(grid, r, c - 1);
        if (r + 1 < x && grid[r + 1][c] == '1')
            dfs(grid, r + 1, c);
        if (c + 1 < y && grid[r][c + 1] == '1')
            dfs(grid, r, c + 1);
    }
}