Go: #include <bits/stdc++.h>
using namespace std;
static const int WHITE = 0;
static const int GRAY  = 1;
static const int BLACK = 2;
static const int N     = 100;

int n, tt;
vector<vector<int>> M(N, vector<int>(N));
vector<int> color(N), d(N), f(N);

void dfs_visit(int u) {
  color[u] = GRAY;
  d[u]     = ++tt;
  for (int v = 0; v < n; v++) {
    if (M[u][v] == 0) continue;
    if (color[v] == WHITE) { dfs_visit(v); }
  }
  color[u] = BLACK;
  f[u]     = ++tt;
}

void dfs() {
  tt = 0;

  for (int u = 0; u < n; u++) {
    if (color[u] == WHITE) dfs_visit(u);
  }
  for (int u = 0; u < n; u++) {
    printf("%d %d %d\n", u + 1, d[u], f[u]);
  }
}

int main() {
  int u, v, k;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> u >> k;
    u--;
    for (int j = 0; j < k; j++) {
      cin >> v;
      v--;
      M[u][v] = 1;
    }
  }

  dfs();
}

C++: #include <iostream>
#include <vector>
#include <stack>

using namespace std;

struct Node {
    bool visit = false;
    vector<int> next;
    int position = 0;
    int start;
    int end;
};

int main() {
    int n, id, k, temp, time = 1;
    Node node[101];
    stack<int> st;

    cin >> n;
    for (int i = 0; i < n; i++) {
        cin >> id >> k;
        for (int j = 0; j < k; j++) {
            cin >> temp;
            node[id].next.push_back(temp);
        }
    }

    node[1].start = time++;
    st.push(1);
    while (!st.empty()) {
        temp = st.top();
        if (node[temp].position < node[temp].next.size() && node[node[temp].next[node[temp].position]].visit == false) {
            node[node[temp].next[node[temp].position]].start = time++;
            st.push(node[temp].next[node[temp].position++]);
        }
        else {
            node[temp].visit = true;
            node[temp].end = time++;
            st.pop();
        }
    }

    for (int i = 1; i <= n; i++) {
        cout << i << " " << node[i].start << " " << node[i].end << endl;
    }

    return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

int discover(int &t, int node, int n, vector<vector<int>> &g, vector<int> &d, vector<int> &f);

int main()
{
	int n;
	cin >> n;
	vector<vector<int>> g(n+1);
	for (int i=1;i<=n;++i)
	{
		int u,k;
		cin >> u >> k;
		for (int j=0;j<k;++j)
		{
			int v;
			cin >> v;
			g[u].push_back(v);
		}
	}

	vector<int> d(n+1);
	vector<int> f(n+1);
	stack<int> st;

	for (int i=1;i<=n;++i)
	{
		d[i]=-1;
		f[i]=-1;
	}


	int t=0;
	for (int i=1;i<=n;++i)
	{
		if (d[i]<0)
		{
			d[i]=++t;
			discover(t,i,n,g,d,f);
			//f[i]=++t;
		}
	}

	for (int i=1;i<=n;++i)
	{
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
}


int discover(int &t, int node, int n, vector<vector<int>> &g, vector<int> &d, vector<int> &f)
{

	for (int i=0;i<g[node].size();++i)
	{
		int nn=g[node][i];
		if (d[nn]<0)
		{
			++t;
			d[nn]=t;
			discover(t,nn,n,g,d,f);
		}
	}

	++t;
	f[node]=t;

	return 0;
}

C++: #define _CRT_SECURE_NO_WARNINGS
#define MAX 2000000000
#include <iostream>
#include <algorithm>
#include <stack>
using namespace std ;

int d[102] = { 0 }, f[102] = { 0 };
int M[102][102];

int main() {
	stack<int> stk;
	int n;
	cin >> n;
	for (int i = 1;i <= n;i++) {
		int k,l,m;
		cin >> m;
		cin >> k;
		for (int j = 0;j < k;j++) {
			cin >> l;
			M[m][l] = 1;
		}
	}
    
	stk.push(1);

    int i = 1,time=1;
    d[1]=1;
	while (!stk.empty()) {
		if (M[stk.top()][i] == 1 && d[i] == 0) {
			stk.push(i);
			time++;
			d[i] = time;
			i = 1;
		}
		else {
			i++;
			if (i > n) {
			    time++;
				f[stk.top()] = time;
				stk.pop();
				i=1;
			}
		}
	}

	for (int i = 1;i <= n;i++) {
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
  
}

C++: #include<iostream>
#define FOR(i,a,b) for (int i=(a);i<(b);i++)
using namespace std;
int G[100][100] = {};
int time = 0;
typedef struct ANS
{
	int id, t, e;
	bool done;
};

void rec(ANS a[],int t)
{
	::time++;
	a[t].t = ::time;
	a[t].done = true;
	FOR(i, 0, 100)
	{
		if (G[t][i] == 1 && a[i].done == false)
		{
			rec(a, i);
		}
	}
	::time++;
	a[t].e = ::time;
}

int main()
{
	ANS ans[101];
	int n;
	cin >> n;
	FOR(i, 0, n)
	{
		ans[i].id = i + 1;
		ans[i].done = false;
		int u, m;
		cin >> u >> m;
		FOR(j, 0, m)
		{
			int l;
			cin >> l;
			G[u - 1][l - 1] = 1;
		}
	}
	rec(ans, 0);
	FOR(i, 0, n)
	{
		cout << ans[i].id << " " << ans[i].t << " " << ans[i].e << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < n; i++)
using namespace std;
typedef long long ll;

int n, t = 0;
vector<vector<int> > G(110);
pair<int, int> toki[110];
bool vis[110];

void dfs(int v)
{
    if(vis[v]) return;
    t++;
    toki[v].first = t;
    vis[v] = true;
    rep(i, G[v].size())
    {
        if(vis[G[v][i]]) continue;
        dfs(G[v][i]);
    }
    t++;
    toki[v].second = t;
    return;
}

int main(void)
{
    cin >> n;
    rep(i, n) vis[i] = false;
    rep(i, n)
    {
        int t, k;
        cin >> t >> k;
        t--;
        rep(j, k)
        {
            int v;
            cin >> v;
            v--;
            G[t].push_back(v);
        }
    }
    rep(i, n)
    {
        dfs(i);
    } 
    rep(i, n)
    {
        cout << i+1 << " " << toki[i].first << " " << toki[i].second << endl;
    }
    return 0;
}

C++: #include <iostream>
#include <stack>
using namespace std;
int d[101],f[101],G[101][101];
stack<int>s;
int n,t;
void dfs(int u)
{
    s.push(u);
    d[u]=t++;
    int i;
    while(!s.empty()){
        u=s.top();
        for(i=1;i<=n;i++)
        {
            if(G[u][i]==1 && d[i]==0)
            {
                s.push(i);
                d[i]=t++;
                //u=i;
                break;
            }
        }
        if(i>n)
        {
            f[s.top()]=t++;
            s.pop();
        }
    }
}
int main()
{
    int k,u,v;
    cin>>n;
    for(int i=1;i<=n;i++){
        d[i]=0;
        for(int j=1;j<=n;j++)
            G[i][j]=0;
    }
    for(int i=0;i<n;i++)
    {
        cin>>u>>k;
        for(int j=0;j<k;j++)
        {
            cin>>v;
            G[u][v]=1;
        }
    }
    t=1;
    for(int i=1;i<=n;i++)
    {
        if(d[i]==0)
            dfs(i);
    }
    for(int i=1;i<=n;i++)
    {
        cout<<i<<' '<<d[i]<<' '<<f[i]<<endl;
    }
    return 0;
}