check cycle directed graph : graph coloring method

/*
0-------------->unvisited
1-------------->processing in dfs
2-------------->processed
*/

class Solution {
    bool cycle(int src,map<int,vector<int>> &adj,vector<int> &vis){
        if (vis[src]==1)
            return true;//you came back to ancestor node......cycle here
        vis[src]=1;//make it as processing
        for(auto node:adj[src]){
            if (vis[node]!=2){
               if (cycle(node,adj,vis))
                   return true;
            }
        }
        vis[src]=2;//make it as processed
        return false;
    }

public:
    bool canFinish(int n, vector<vector<int>>& p) {
        vector<int> vis(n,0);
        map<int,vector<int>> adj;
        for(auto x:p)
            adj[x[0]].push_back(x[1]);

        for(int i=0;i<n;++i)
            if (vis[i]==0){
                if (cycle(i,adj,vis))
                    return false;
            }
        return true;

    }
};