1 int dx[4]={1,-1,0,0};
 2 int dy[4]={0,0,1,-1}; 
 3 void dfs(char** grid, int gridSize, int* gridColSize,int x,int y)
 4 {
 5     int i,j;
 6     for(i=0;i<4;i++){
 7         int nx=x+dx[i],ny=y+dy[i];
 8         if(nx>=0&&nx<gridSize&&ny>=0&&ny<gridColSize[0]&&grid[nx][ny]=='1'){
 9             grid[nx][ny]='0';
10             dfs(grid,gridSize,gridColSize,nx,ny);
11         }
12     }
13     return ;
14 }
15 int numIslands(char** grid, int gridSize, int* gridColSize){ 
16     int i,j,res=0;
17     for(i=0;i<gridSize;i++){
18         for(j=0;j<gridColSize[0];j++){
19             if(grid[i][j]=='1'){
20                 dfs(grid,gridSize,gridColSize,i,j);
21                 res++;
22             }
23         }
24     }
25     return res;   
26 }