Go: package main

import (
	"bufio"
	"fmt"
	"os"
	"strconv"
)

type vertexId int

type vertex struct {
	id vertexId
	firstVisitAt int
	finishVisitAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		firstVisitAt: 0,
		finishVisitAt: 0,
		adjs: adjs,
	}
}

func (v *vertex) doesAllAdjsVisited(vertices []vertex) bool {
	for _, vId := range v.adjs {
		adj := vertices[vId-1]
		if !adj.isVisited() {
			return false
		}
	}
	return true
}

func (v *vertex) isFirstVisit() bool {
	return v.firstVisitAt == 0
}

func (v *vertex) isVisited() bool {
	return v.firstVisitAt > 0
}

func (v *vertex) nextVertex(vertices []vertex) (vertexId, error) {
	for _, vId := range v.adjs {
		adj := vertices[vId-1]
		if !adj.isVisited() {
			return vId, nil
		}
	}
	return vertexId(-1), fmt.Errorf("illegal")
}

func dfs(currentId vertexId, timestamp int, vertices []vertex) int {
	timestamp = timestamp + 1
	currentVertex := &vertices[currentId-1]
	if currentVertex.isFirstVisit() {
		currentVertex.firstVisitAt = timestamp
	}
	for !currentVertex.doesAllAdjsVisited(vertices) {
		nextVertexId, _ := currentVertex.nextVertex(vertices)
		timestamp = dfs(nextVertexId, timestamp, vertices)
	}
	timestamp = timestamp + 1
	currentVertex.finishVisitAt = timestamp
	return timestamp
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	dfs(vertexId(1), 0, vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", vertices[i].id, vertices[i].firstVisitAt, vertices[i].finishVisitAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}

C++: #include <stdio.h>
#include <iostream>
#include <utility>
#include <algorithm>
#include <math.h>
#include <vector>
#include <list>

using namespace std;
int n;
list<int> adj[101];
int d[101] = {};
int f[101] = {};

void DFS(int v)
{
    static int num = 1;
    d[v] = num++;
    while (!adj[v].empty())
    {
        if (d[adj[v].front()] == 0)
            DFS(adj[v].front());
        adj[v].pop_front();
    }
    f[v] = num++;
}

void print()
{
    for (int i = 1; i <= n; i++)
    {
        printf("%d %d %d\n", i, d[i], f[i]);
    }
}

int main()
{
    int u, k, v;
    cin >> n;

    for (int i = 0; i < n; i++)
    {
        cin >> u >> k;
        while (k > 0)
        {
            cin >> v;
            adj[u].push_back(v);
            k--;
        }
    }
    for (int i = 1; i <= n; i++)
        if (d[i] == 0)
            DFS(i);

    print();

    return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <vector>

using namespace std;
const int maxn=100+10;
int n;
vector<int> g[maxn];
int s[maxn],e[maxn];
int vis[maxn];
int t=1;
void dfs(int u)
{
    vis[u]=1;
    s[u]=t++;
    for(int i=0;i<g[u].size();i++)
    {
        int v=g[u][i];
        if(!vis[v])
        {
            dfs(v);
        }
    }
    e[u]=t++;
}
int main()
{
//    freopen("in.txt","r",stdin);
    scanf("%d",&n);
    int no,cnt,dd;
    for(int i=0;i<n;i++)
    {
        scanf("%d%d",&no,&cnt);
        for(int j=0;j<cnt;j++)
        {
            scanf("%d",&dd);
            g[no-1].push_back(dd-1);
        }
    }
    dfs(0);
    for(int i=0;i<n;i++)
    {
        printf("%d %d %d\n",i+1,s[i],e[i]);
    }
    return 0;
}

C++: #include<iostream>
#include<stack>
using namespace std;
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n,M[N][N];
int color[N],d[N],f[N],tt;
int nt[N];

int next(int u)
{
    for(int v=nt[u];v<n;v++)
    {
        nt[u]=v+1;
        if(M[u][v])return v;
    }
    return -1;
}

void dfs_visit(int r)
{
    for(int i=0;i<n;i++)
    {
        nt[i]=0;
    }

    stack<int> s;
    s.push(r);
    color[r]=GRAY;
    d[r]=++tt;

    while(!s.empty())
    {
        int u=s.top();
        //cout << "s.top=" << u << endl;
        int v=next(u);
        //cout << "u.next=" << v << endl;
        if(v!=-1)
        {
            if(color[v]==WHITE)
            {
                color[v]=GRAY;
                d[v]=++tt;
                s.push(v);
            }
        }
        else
        {
            s.pop();
            color[u]=BLACK;
            f[u]=++tt;
        }
    }
}

void dfs()
{
    for(int i=0;i<n;i++)
    {
        color[i]=WHITE;
        nt[i]=0;
    }


    tt=0;

    for(int u=0;u<n;u++)
    {
        if(color[u]==WHITE)
        {
            //cout << "visit " << u << endl;
            dfs_visit(u);
        }
    }

    for(int i=0;i<n;i++)
    {
        cout << i+1 << " " << d[i] << " " << f[i] << endl;
    }
}

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

    for(int i=0;i<n;i++)
    {
        cin >> u;//row
        if(i==u-1)
        {
            cin >> node;//number of node
            for(int j=0;j<node;j++)
            {
                cin >> v;
                M[i][v-1]=1;
            }
        }
    }

    /*
    for(int i=0;i<n;i++)
    {
        for(int j=0;j<n;j++)
        {
            cout << M[i][j] << " " ;
        }
        cout << endl;
    }*/

    dfs();
    return 0;
}

C++: #ifdef LOCAL_BUILD
#include "pch.h"
#define DLOG(msg) cout << "#" << __LINE__ << ":" << msg << endl;
#define DLOG_V(var) \
  cout << "#" << __LINE__ << ":" << #var << " : " << var << endl;
#else
#include <bits/stdc++.h>
#define DLOG(msg)
#define DLOG_V(var)
#endif
using namespace std;

constexpr auto no_value = numeric_limits<uint64_t>::max();

struct GraphParser {
  GraphParser(vector<vector<int>>& edges_)
      : edges(edges_), start(edges.size(), 0), end(edges.size(), 0) {
    //
  }

  void run() {
    t = 0;
    for (size_t i = 0; i < edges.size(); ++i) {
      if (!start[i]) {
        recur(i);
      }
    }
  }

  vector<vector<int>>& edges;
  vector<int> start;
  vector<int> end;
  int t;

 private:
  void recur(int cur) {
    if (start[cur]) {
      return;
    }
    start[cur] = ++t;
    for (auto&& e : edges[cur]) {
      recur(e);
    }
    end[cur] = ++t;
  }
};

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

  GraphParser p(edges);
  p.run();
  for (int i = 0; i < n; ++i) {
    cout << (i + 1) << " " << p.start[i] << " " << p.end[i] << endl;
  }
}

C++: // 2015/01/05 Tazoe

#include <iostream>
#include <stack>
using namespace std;

int main()
{
	int n;
	cin >> n;

	int G[100][100] = {0};

	for(int i=0; i<n; i++){
		int u, k;
		cin >> u >> k;

		for(int j=0; j<k; j++){
			int v;
			cin >> v;

			G[u-1][v-1] = 1;
		}
	}

//	for(int i=0; i<n; i++){
//		for(int j=0; j<n; j++){
//			cout << G[i][j] << ' ';
//		}
//		cout << endl;
//	}

	int d[100] = {0};
	int f[100] = {0};

	stack<int> S;
	int T = 0;

	S.push(0);
	d[0] = ++T;

	while(!S.empty()){
		int u = S.top();

		int v = -1;
		for(int j=0; j<n; j++){
			if(G[u][j]==1 && d[j]==0){
				v = j;
				break;
			}
		}

		if(v!=-1){
			S.push(v);
			d[v] = ++T;
		}
		else{
			S.pop();
			f[u] = ++T;
		}
	}

	for(int i=0; i<n; i++){
		cout << i+1 << ' ' << d[i] << ' ' << f[i] << endl;
	}

	return 0;
}