Number of Operations to Make Network Connected

class Solution {
public:

  void dfs(vector<int> adj[], vector<bool> &visited, int src)
    {
        visited[src] = true;
        for(int i : adj[src]){
            if(!visited[i]){
                dfs(adj, visited, i);
            }
        }
    }
    int makeConnected(int n, vector<vector<int>>& connections) {
         if(connections.size()<n-1)
        {
            return -1;
        }
        vector<int> gr[n];
        for(auto cable : connections){
            gr[cable[0]].push_back(cable[1]);
            gr[cable[1]].push_back(cable[0]);
        }

            int ans=0;
            vector<bool> visited(n,0);
            for(int i=0;i<n;i++)
            {
                if(!visited[i])
                {
                    dfs(gr,visited,i);
                     ans++;
                }

            }
            return ans-1;


    }
};