class Solution {
public:
int numIslands(vector<vector<char>>& grid) {
int res=0;
int m=grid.size(),n=grid0.size();
for(int i=0;i<m;i++){
for(int j=0;j<n;j++){
if(gridij=='1'){
//发现岛屿数量加1
res++;
//淹没岛屿
dfs(grid,i,j);
}
}
}
return res;
}
void dfs(vector<vector<char>>& grid,int i,int j){
int m=grid.size(),n=grid0.size();
//超出边界
if(i<0||j<0||i>=m||j>=n){
return;
}
//已经是海水
if(gridij=='0'){
return;
}
gridij='0';
dfs(grid,i+1,j);
dfs(grid,i-1,j);
dfs(grid,i,j+1);
dfs(grid,i,j-1);
}
};