力扣第200题，怎么打印输出啊，搞半天了还不行

Question

public class demoMedium200 {
    public static void main(String[] args) {
        demoMedium200 invoke = new demoMedium200();
       char[][] grid = {{"1","1","1","1","0"},{"1","1","0","1","0"},{"1","1","0","0","0"},{"0","0","0","0","0"}}


        System.out.println(invoke.numIslands(grid));


    }
    void dfs(char[][] grid, int r, int c) {
        int nr = grid.length;
        int nc = grid[0].length;

        if (r < 0 || c < 0 || r >= nr || c >= nc || grid[r][c] == '0') { //如果现在的行数小于0或现在的列数小于0或现在的行数大于等于岛屿的行数+1或者列数大于等于岛屿的列数或这个网格的value值是0
            return;//就结束这部分数据存储有关的栈帧
        }

        grid[r][c] = '0';
        dfs(grid, r - 1, c);
        dfs(grid, r - 1, c);
        dfs(grid, r - 1, c);
        dfs(grid, r - 1, c);
    }

    public int numIslands(char[][]grid){
        if(grid == null || grid.length==0) {
            return 0;
        }

        int nr = grid.length;
        int nc = grid[0].length;
        int num_islands = 0;
        for(int r = 0 ; r < nr ; ++r){
            for (int c = 0; c<nc; ++c){
            if (grid[r][c] =='1'){
                ++num_islands;
                dfs(grid, r ,c);

            }}


        }
        return num_islands;
    }
    }

Answer 1

如果有帮助到你，希望采纳支持谢谢！！！

public class demoMedium200 {

    public static void main(String[] args) {
        demoMedium200 d200 = new demoMedium200();
        // 示例①
        char[][] grid1 = { { '1', '1', '1', '1', '0' }, { '1', '1', '0', '1', '0' }, { '1', '1', '0', '0', '0' },
                { '0', '0', '0', '0', '0' } };
        System.out.println(d200.numIslands(grid1));
        // 示例②
        char[][] grid2 = { { '1', '1', '0', '0', '0' }, { '1', '1', '0', '0', '0' }, { '0', '0', '1', '0', '0' },
                { '0', '0', '0', '1', '1' } };
        System.out.println(d200.numIslands(grid2));

    }

    public void dfs(char[][] grid, int r, int c) {
        int nr = grid.length;
        int nc = grid[0].length;

        if (r < 0 || c < 0 || r >= nr || c >= nc || grid[r][c] == '0') {
            return;
        }

        grid[r][c] = '0';
        dfs(grid, r - 1, c);
        dfs(grid, r + 1, c);
        dfs(grid, r, c - 1);
        dfs(grid, r, c + 1);
    }

    public int numIslands(char[][] grid) {
        if (grid == null || grid.length == 0) {
            return 0;
        }

        int nr = grid.length;
        int nc = grid[0].length;
        int num_islands = 0;
        for (int r = 0; r < nr; ++r) {
            for (int c = 0; c < nc; ++c) {
                if (grid[r][c] == '1') {
                    ++num_islands;
                    dfs(grid, r, c);
                }
            }
        }

        return num_islands;
    }

}

程序运行截图：