Detect cycle in a directed graph

bool helper(int node, map<int,bool>&visited, map<int,bool>&instack,vector<int> adj[])
{
    visited[node]=true;
    instack[node]=true;
    
    for(auto x:adj[node])
    {
        if((!visited[x] && helper(x,visited,instack,adj))|| instack[x])
            return true;
    }
    
    instack[node]=false;
    return false;
    
}




bool isCyclic(int v, vector<int> adj[])
{
   map<int,bool>visited; map<int,bool>instack;
   bool ans=false;
   
   for(int i=0;i<v;i++)
   {
       if(adj[i].size()==0)
          continue;
       else if(!visited[i])
         ans=(ans||helper(i,visited,instack,adj));
         
       if(ans)
         return ans;
   }
   
    return false;
}