200

class Solution {
public:
void find(int i,int j,vector<vector<char>>& grid,vector<vector<int>>& vis){
    int n=grid.size();
    int m=grid[0].size();
    if(i>n-1 || i<0 || j<0 || j>m-1 || vis[i][j]==1)
    return;

    vis[i][j]=1;
    if(i+1<n){
        if(grid[i+1][j]=='1' && vis[i+1][j]==0){
            find(i+1,j,grid,vis);
        }
    }
    if(i-1>=0){
        if(grid[i-1][j]=='1' && vis[i-1][j]==0){
            find(i-1,j,grid,vis);
        }
    }
    if(j+1<m){
        if(grid[i][j+1]=='1' && vis[i][j+1]==0){
            find(i,j+1,grid,vis);
        }
    }
    if(j-1>=0){
        if(grid[i][j-1]=='1' && vis[i][j-1]==0){
            find(i,j-1,grid,vis);
        }
    }
    return ;
    
}

    int numIslands(vector<vector<char>>& grid) {
        int n=grid.size();
        int m=grid[0].size();
        vector<vector<int>> vis(n,vector<int>(m,0));
        int c=0;
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                if(grid[i][j]=='1' && vis[i][j]==0){
                find(i,j,grid,vis);
                c++;
                }
            }
        }
        return c;
    }
};