思路：
经典岛屿变种


代码：

import java.util.*;


class Solution {
    boolean visit[][];
    boolean touch=false;
    List<int[]>list;
    public int[][] solve(int[][] grid) {
        // Write your code here
        int r=grid.length;
        int c=grid[0].length;
        visit=new boolean[r][c];
        
        for(int i=0;i<r;i++){
            for(int j=0;j<c;j++){
                if(grid[i][j]==0||visit[i][j])continue;
                touch=false;
                list=new ArrayList<>();
                dfs(grid,i,j);
                if(!touch){
                    for(int A[]:list){
                        grid[A[0]][A[1]]=0;
                    }
                }
                
            }
        }
        return grid;
    }
    
    public void dfs(int grid[][],int i,int j){
        if(i<0||j<0||i>=grid.length||j>=grid[0].length){
            touch=true;
            return;
        }
        if(visit[i][j])return;
        if(grid[i][j]==0)return;
        visit[i][j]=true;
        list.add(new int[]{i,j});
        dfs(grid,i+1,j);
        dfs(grid,i-1,j);
        dfs(grid,i,j+1);
        dfs(grid,i,j-1);
    }
}