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

func dfs(currentId vertexId, timestamp int, vertices []vertex) int {
	currentVertex := &vertices[currentId-1]
	if currentVertex.isVisited() {
		return timestamp
	}
	timestamp = timestamp + 1
	currentVertex.firstVisitAt = timestamp
	for _, adjId := range currentVertex.adjs {
		timestamp = dfs(adjId, timestamp, vertices)
	}
	timestamp = timestamp + 1
	currentVertex.finishVisitAt = timestamp
	return timestamp
}

func solveDfs(vertices []vertex) {
	timestamp := 0
	for {
		vid := vertexId(-1)
		for i := 0; i < len(vertices); i++ {
			if !vertices[i].isVisited() {
				vid = vertexId(i+1)
				break
			}
		}
		if vid > 0 {
			timestamp = dfs(vid, timestamp, vertices)
		} else {
			break
		}
	}
}

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)
	}

	solveDfs(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 <bits/stdc++.h>
using namespace std;

int t;
vector<int> d, f;
int n;
vector<vector<int> > G;

void dfs(int v) {
  if ( d[v] ) return;
  d[v] = ++t;  

  for ( int i = 0; i < n; i++ ) {
    if ( G[v][i] ) dfs(i);
  }

  f[v] = ++t;  
}

int main() {
  cin >> n;

  d = vector<int>(n, 0);
  f = vector<int>(n, 0);

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

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

  dfs(0);

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

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

typedef long long ll;

ll d[100], f[100], now, cnt;
char flag[100];
vector<int> vec[100];

int dfs(int n) {
  if(flag[n]) return 0;
  flag[n] = 1;
  cnt++;
  d[n] = cnt;
  vector<int>::iterator it;
  for(it = vec[n].begin(); it != vec[n].end(); ++it) {
    if(!flag[*it]) dfs(*it);
  }
  ++cnt;
  f[n] = cnt;
  return 0;
}

int main(void) {
  ll n;
  scanf("%d", &n);
  now = 0, cnt = 0;
  rep(i, n) flag[i] = 0;
  rep(i, n) {
    int u, k;
    scanf("%d%d", &u, &k);
    u--;
    rep(j, k) {
      int v;
      scanf("%d", &v);
      v--;
      vec[u].push_back(v);
    }
    sort(vec[u].begin(), vec[u].end());
  }
  now = 0;
  while( 1 ) {
    dfs(now);
    int s = 1, i;
    for(i = 0; i < n; ++i) if(!flag[i]){
      s = 0;
      break;
    }
    if(s) break;
    else now = i;
    //rep(j, n) printf("%d ", (int)flag[j]);
    //printf("%d\n", i);
    //return 0;
  }
  rep(i, n) printf("%d %lld %lld\n", i + 1, d[i], f[i]);
  return 0;
}

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

const int MAX = 100;
int n;
int G[MAX + 1][MAX + 1];
int bt[MAX + 1], et[MAX + 1];
int states[MAX + 1];
int t = 1;

void dfs(int id) {
  states[id] = 1;
  bt[id] = t;
  for (int i = 0; i < n; i++) {
    if (G[id][i] == 1 && states[i] == 0) {
      t++;
      dfs(i);
    }
  }
  et[id] = ++t;
}

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

  cin >> n;

  int u, v, k;

  for (int i = 0; i < n; i++) {
    states[i] = 0;
    for (int j = 0; j < n; j++) {
      G[i][j] = 0;
    }
  }

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

  dfs(0);

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

  return 0;
}

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

//??¶????????°
int n;
//?????\??????
int M[N][N];
//??°?????¶???????¢????
int color[N];
//??\??¶????????°??¶???
int d[N];
//??\??¶???????????¶???
int f[N];
//??¶???
int tt;
//???????????????????????????????????????
//?????¨?????????????????¨????????\??????????????????
int nt[N];

//????????????????????????u?????????v
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();
        int v=next(u);
        if(v!=-1&&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++)
        nt[i]=0,color[i]=WHITE;
    tt=0;

    //??\????????????u?????????????????±?????????????´¢
    for(int u=0;u<n;u++)
        if(color[u]==WHITE)
            dfs_visit(u);

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

int main(){
    int u,k,v;

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

    dfs();
}

C++: #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();
}