Go: package main

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

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)
	sc.Scan()
	num, _ := strconv.Atoi(sc.Text())
	nodes := make(map[int]*node)

	for i := 0; i < num; i++ {
		sc.Scan()
		id, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		nodeNum, _ := strconv.Atoi(sc.Text())
		n := node{id, make([]int, 0), 0, 0}
		for j := 0; j < nodeNum; j++ {
			sc.Scan()
			nid, _ := strconv.Atoi(sc.Text())
			n.nexts = append(n.nexts, nid)
		}
		nodes[id] = &n
	}

	s := Stack{}
	for i := 1; i < len(nodes)+1; i++ {
		if nodes[i].s != 0 {
			continue
		}
		walk(i, &nodes, s)
	}
	for i := 1; i < len(nodes)+1; i++ {
		fmt.Printf("%v %v %v\n", (*nodes[i]).id, (*nodes[i]).s, (*nodes[i]).e)
	}
}

var time int

func walk(nid int, nodes *map[int]*node, s Stack) {
	n := (*nodes)[nid]
	if n.s != 0 {
		return
	}
	time++
	n.s = time
	s.Push(n)
	for _, v := range n.nexts {
		walk(v, nodes, s)
	}
	time++
	n.e = time
}

type node struct {
	id    int
	nexts []int
	s     int
	e     int
}

// Stack is Stack
type Stack struct {
	stack []interface{}
}

// Push new value
func (stack *Stack) Push(val interface{}) {
	stack.stack = append(stack.stack, val)
}

// Pop new value
func (stack *Stack) Pop() interface{} {
	val := stack.stack[len(stack.stack)-1]
	stack.stack = stack.stack[0 : len(stack.stack)-1]
	return val
}

C++: #include <algorithm>
#include <cstdio>
#include <iostream>
#include <map>
#include <cmath>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
#include <stdlib.h>
#include <stdio.h>
#include <bitset>
using namespace std;
#define FOR(I,A,B) for(int I = (A); I < (B); ++I)
typedef long long ll;

int d[111], f[111];
bool visited[111];
vector<vector<int> > g(111);
int t;
void dfs(int x){
  t++;
  d[x] = t;
  visited[x] = true;
  for(auto &u : g[x]){
    if(!visited[u]){
      dfs(u);
    }
  }
  t++;
  f[x] = t;
}

int main(){
  int n; cin >> n;
  FOR(i,0,n){
    int u, k; cin >> u >> k;
    FOR(j,0,k){
      int v;
      cin >> v;
      g[u].push_back(v);
    }
  }
  FOR(i,0,n+1) visited[i] = false;
  t = 0;
  FOR(i,1,n+1){
    if(!visited[i]) dfs(i);
  }

  FOR(i,1,n+1){
    printf("%d %d %d\n", i, d[i], f[i]);
  }
  return 0;
}

C++: #include <iostream>
#include <vector>
using namespace std;

int n;
int t; //mytime?????????????????§???????´?
int mytime1[110],mytime2[110]; //?????§??????
int G[110][110];
int c[110];

void dfs(int cur){
	t+=1;
	mytime1[cur]=t;
	c[cur]=1;
	for(int dst=0; dst<n; ++dst){
		if(G[dst][cur]==1&&c[dst]==0){
			dfs(dst);
		}
	} 
	t += 1;
	mytime2[cur]=t;
}


int main()
{
	vector<int> v[110];
	cin>>n;
	for(int i=0;i<n;i++){
		int u,k;
		cin>>u>>k;
		for(int j=0;j<k;j++){
			int tmp;
			cin>>tmp;
			v[u].push_back(tmp);
		}
	}
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			G[i][j]=0;
		}
	}
	for(int i=1;i<n+1;i++){
		for(int j=0;j<v[i].size();j++){
			G[i-1][v[i][j]-1]=1; //
		}
	}
	for(int i=0;i<n;++i){
		dfs(i);
		cout<<(i+1)<<' '<<mytime1[i+1]<<" "<<mytime2[i+1] <<endl;
}
}

C++: #include <stdio.h>
#define MAX_N (105)

int n;
int G[MAX_N + 1][MAX_N + 1];
int d[MAX_N + 1];		// ????????????
int f[MAX_N + 1];		// ????????????
int time;
int dfs(int cur)
{
    d[cur] = time;
    for ( int i = 1; i <= n; i++ ) {
	if ( G[cur][i] && (d[i] == 0)) {
	    time++;
	    dfs(i);
	}
    }
    time++;
    f[cur] = time;
}

int main()
{
    scanf("%d", &n);
    
    for ( int i = 0; i < n; i++ ) {
	int u, k;
	scanf("%d %d", &u, &k);
	for ( int j = 0; j < k; j++ ) {
	    int v;
	    scanf("%d", &v);
	    G[u][v] = 1;
	}
    }

    time = 1;

    dfs(1);

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

void dfs_visit(int r){
    stack<int> S;

    S.push(r);
    color[r] = GRAY;
    d[r] = ++tt;

    while(!S.empty()){
        int u = S.top();
        int v = -1;
        for (int j = 0; j < n; ++j){
            if(M[u][j] == 1 && color[j] == WHITE) {
                v = j;
                break;
            }
        }
        if (v != -1){
            S.push(v);
            color[v] = GRAY;
            d[v] = ++tt;
        } else {
            color[u] = BLACK;
            f[u] = ++tt;
            S.pop();
        }
    }
}

void dfs(){
    int u;
    // initialization
    for( u = 0; u < n; ++u) color[u] = WHITE;
    tt = 0;

    for( u = 0; u < n; ++u){
        if (color[u] == WHITE) dfs_visit(u);
    }

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

int main()
{
    int u, v, k, i, j;
    scanf("%d", &n);

    for (i = 0; i < n; ++i){
        for(j = 0; j < n; ++j){
            M[i][j] = 0;
        }
    }

    for (i = 0; i < n; ++i){
        scanf("%d %d", &u, &k);
        --u;
        for (j = 0; j < k; ++j){
            scanf("%d", &v);
            --v;
            M[u][v] = 1;
        }
    }

    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;
    recur(0);
  }

  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++: #include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <stdio.h>
#include <cmath>
#include <map>
#include <queue>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)

vector<int> d;
vector<int> f;
int t;
void dfs(vector<vector<int>>Graph, int v) {
  d[v] = t;
  t++;
  if(Graph[v].size() == 0) {
    return;
  }
  for(auto next_v: Graph[v]) {
    if(d[next_v] != -1) {
      continue;
    }
    //cout << next_v << ":" << t << endl;
    dfs(Graph, next_v);
    f[next_v] = t;
    t++;
  }
  f[v] = t;
}

int main() {
  int n;
  cin >> n;
  vector<vector<int>> Graph(n);
  rep(i, n) {
    int u, k;
    cin >> u >> k;
    rep(j, k) {
      int a;
      cin >> a;
      Graph[i].push_back(a-1);
    }
  }
  d = f = vector<int>(n, -1);
  d[0] = 1;
  t = 1;
  dfs(Graph, 0);
  f[0] = t;
  rep(i, n) {
    if(d[i] == -1) {
      t++;
      dfs(Graph, i);
      //f[i] = t;
    }
  }
  rep(i, n) {
    cout << i + 1 << " ";
    cout << d[i] << " ";
    cout << f[i] << endl;
  }
}