(GFG POTD) Number Of Islands

class Solution {
  public:
  vector<vector<int>>grid;
  int n,m;
  void dfs(vector<vector<int>>&visited,int i,int j)
    {
        if(i<0 || j<0)
        {
            return;
        }
        if(i>=n || j>=m)
        {
            return;
        }
        if(grid[i][j]==0 || visited[i][j]==1)
        {
            return;
        }
        visited[i][j]=1;
        dfs(visited,i+1,j);
        dfs(visited,i-1,j);
        dfs(visited,i,j+1);
        dfs(visited,i,j-1);
    }
  int no_of_islands()
  {
      int cnt=0;
        // n=grid.size();
        // m=grid[0].size();
        vector<vector<int>>visited;
        for(int i=0;i<n;i++)
        {
            vector<int>temp;
            for(int j=0;j<m;j++)
            {
                temp.push_back(-1);
            }
            visited.push_back(temp);
        }
        for(int i=0;i<n;i++)
        {
            for(int j=0;j<m;j++)
            {
                if(visited[i][j]==-1 && grid[i][j]==1)
                {
                    dfs(visited,i,j);
                    cnt++;
                }
            }
        }
        return cnt;
  }
    vector<int> numOfIslands(int n1, int m1, vector<vector<int>> &operators) {
        // code here
        n=n1;
        m=m1;
        for(int i=0;i<n;i++)
        {
            vector<int>t;
            for(int j=0;j<m;j++)
            {
                t.push_back(0);
            }
            grid.push_back(t);
        }
        vector<int>ans;
        for(int i=0;i<operators.size();i++)
        {
            grid[operators[i][0]][operators[i][1]]=1;
            int n=no_of_islands();
            ans.push_back(n);
        }
        return ans;
    }
};