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<bits/stdc++.h>
using namespace std;
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (a>b) { a=b; return 1; } return 0; }

using Lint=long long;
using Graph=vector<vector<int>>;

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int N; cin>>N;
    Graph G(N);
    for(int i=0;i<N;i++){
        int u,k; cin>>u>>k;
        u--;
        while(k--){
            int v; cin>>v;
            v--;
            G[u].push_back(v);
        }
    }
    vector<int> d(N,-1),f(N);
    int time=1;
    function<void(int)> dfs=[&](int v)
    {
        d[v]=time++;
        for(int u:G[v]) if(d[u]==-1){
            dfs(u);
        }
        f[v]=time++;
    };

    for(int i=0;i<N;i++) if(d[i]==-1){
        dfs(i);
    }
    for(int i=0;i<N;i++){
        cout<<i+1<<' '<<d[i]<<' '<<f[i]<<endl;
    }
    return 0;
}

C++: #include <stdio.h>

int A[101][101];
int ans[101][3];
int an = 1;


int judge(int i, int j){
  if(ans[i][j] == 0){
    ans[i][j] = an;
    an++;
  }
}

int serch(int a[101][101], int  ni, int n){
  int  j;
  
  for(j=0; j<n; j++){
    if(A[ni][j] == 1){
      judge(j, 1);
      serch(A, j, n);
    }
  }
  judge(ni, 2);
}

int  main(){
  int i, j, k, n, x, y;
  
  scanf("%d", &n);
  
  for(i=0; i<n; i++){
    for(j=0; j<n; j++)
      A[i][j] = 0;
    ans[i][0] = i+1;
  }
  
  for(i=0; i<n; i++){
    scanf("%d %d", &x, &y);
    for(j=0; j<y; j++){
      scanf("%d", &k);
      A[i][k-1] = 1;
    }
  }
  
  judge(0, 1);
  
  for(i=0; i<n; i++){
    if(A[0][i] == 1){
      judge(i, 1);
      serch(A, i, n);
    }
  }
  judge(0, 2);
  
  for(i=0; i<n; i++){
    for(j=0; j<3; j++){
      if(j>0)
        printf(" ");
      printf("%d", ans[i][j]);
    }
    printf("\n");
  }
  
  return 0;
}

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

int N;
int a[110][110]={{0}};
int d[110][5]={{0}};
int T=1;

void dfs(int cur);

int main(){
        cin >> N;
        for(int i=0; i<N; i++){
                int v,n;
                cin >> v;
                cin >> n;
                for(int j=0; j<n; j++){
                        int V;
                        cin >> V;
                        a[v-1][V-1]=1;
                }
        }
        dfs(1);
        for(int i=0; i<N; i++){
                cout << i+1 << " ";
                for(int j=0; j<2; j++){
                        cout << d[i][j];
                        if(!j)cout << " ";
                }
        cout << endl;
        }
}


void dfs(int cur){
        d[cur-1][0]=T;
        T++;
        //cerr << "visiting_" << cur << " " << T << endl;
        for(int i=0; i<N; i++){
                if(a[cur-1][i] && !d[i][0]){
                        dfs(i+1);
                }
        }
        d[cur-1][1]=T;
        T++;
        if(cur>1)cur--;
}

C++: #include <iostream>
using namespace std;
int color[101],d[101],f[101],t;
int a[101][101]={};
// white 0 gray 1 brack 2
void DFSvisit(int n,int u){
    t++;
    d[u]=t;
    color[u]=1;
    for(int i=1;i<=n;i++){
        if(a[u][i]==1 && color[i]==0){
            DFSvisit(n,i);
        }
    }
    color[u]=2;
    t++;
    f[u]=t;
}
void DFS(int n){
    for(int i=1;i<=n;i++){
        color[i]=0;
    }
    t=0;
    for(int i=1;i<=n;i++){
        if(color[i]==0){
            DFSvisit(n,i);
        }
    }
}
int main(){
    int n,k,m,l;
    cin>>n;
    for(int i=0;i<n;i++){
        cin>>m>>k;
        for(int j=0;j<k;j++){
            cin>>l;
            a[m][l]=1;
        }
    }
    DFS(n);
    for(int i=1;i<=n;i++){
        cout<<i<<" "<<d[i]<<" "<<f[i]<<endl;
    }
    return 0;
}