Go: package main

import (
	"fmt"
)

func main() {
	var n int
	fmt.Scan(&n)
	g := make([][]int, n+1)
	for i := 0; i < n; i++ {
		var u,k int
		fmt.Scan(&u)
		fmt.Scan(&k)
		g[u] = make([]int, k)
		for j := 0; j < k; j++ {
			fmt.Scan(&g[u][j])
		}
	}

	d := make([]int, n+1)
	f := make([]int, n+1)
	dfs(&g, &d, &f, 1, 1)

	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d %d\n", i, d[i], f[i])
	}
}

func dfs(g *[][]int, d *[]int, f *[]int, id int, t int) int {
	if (*d)[id] > 0 {
		return t
	}
	(*d)[id] = t
	t += 1
	for i := 0; i < len((*g)[id]); i++ {
		t = dfs(g, d, f, (*g)[id][i], t)
	}
	(*f)[id] = t
	return t+1
}

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

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

  int V[100][100]; //隣接リスト
  int cnt[100]; //各点においてどこまでみたかの把握
  int d[100];
  int f[100];
  int time=1;
  int l=0;
  int come[100]; //その点はどこからきたかの把握

  //初期化
  for(int i=0;i<100;i++){
    for(int j=0;j<100;j++){
      V[i][j]=0;
      cnt[j]=0;
      d[j]=0;
      f[j]=0;
      come[j]=0;
    }
  }
  //グラフ情報の読み込み
 int  m=0;
  for(int i=0;i<n;i++){
    cin>>u;
    cin>>k;
    for(int j=0;j<k;j++){
      cin>>v;
      V[u-1][m]=v;
      m++;
    }
    m=0;
  }


  //スタートは0
 d[0]=1;
 time++;
  while(1){

    if(time==2*n+1) break;
    //先がありかつそこは探索終了していない
    if(V[l][cnt[l]]!=0 && f[V[l][cnt[l]]-1]==0){ 
     
      if(d[V[l][cnt[l]]-1]==0) d[V[l][cnt[l]]-1]=time;

   come[V[l][cnt[l]]-1]=l;
      cnt[l]++;
      l=V[l][cnt[l]-1]-1; 

      time++;
      //先がないまたはさきが探索終了している
    }else{

      if(d[l]==0) d[l]=time;
       f[l]=time;
      l=come[l];
      time++;

    }

  }
  /*
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
    cout<<V[i][j]<<" ";
    if(j==n-1) cout<<endl;
  }
  }
  */
  //出力
  for(int i=0;i<n;i++){

    cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }


  return 0;
}

C++: #include <stdio.h>

int time, n;
int d[100], f[100], color[100];

void dfs(int u) {
    color[u] = 1
    d[u] = ++time;
    for (int i=0; i<n; i++) {
        if(M[u][i] && color[i] == 0) {
            dfs(i);
        }
    }
    color[u] = 2;
    f[u] = ++time;
}

void dfs_init(){
    for (int i=0; i<100; i++) color[i] = 0;
    dfs();
}

int main() {
    int u, k, v;
    scanf("%d", &n);
    
    int M[n][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++) {
        scanf("%d %d", &u, &k);
        for (int j=0; j<k; j++) {
            scanf("%d", &v);
            M[u-1][v-1] = 1;
        }
    }
    
    dfs_init();
    
    for (int i=0; i<n; i++) {
        printf("%d %d %d\n", i, d[i], f[i]);
    }
    return 0;
}

C++: #include <cstdio>
#include <stack>
#include <vector>
using namespace std;
static const int MAX = 101;
int V, tt;
bool visited[MAX];
int disc[MAX], finish_time[MAX];
vector<int> G[MAX];

void dfs(int current) {
      visited[current] = true;
      disc[current] = ++tt;
      for (int i = 0; i < G[current].size(); i++) {
          int next = G[current][i];
          if (!visited[next]) dfs(next);
      }
      finish_time[current] = ++tt;
}

int main()
{
    int k, source, target;
    tt=0;
    scanf("%d", &V);
    for (int i = 0; i < V; i++) {
        scanf("%d %d", &source, &k);
        for (int j = 0; j < k; j++) {
            scanf("%d", &target);
            G[source].push_back(target);
        }
    }

    fill(visited, visited+V+1, 0);
    fill(disc, disc+V+1, 0);
    fill(finish_time, finish_time+V+1, 0);
    for (int i = 1; i <= V; i++) {
        if (!visited[i]) {
            dfs(i);
        }
    }

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

    return 0;
}

C++: /*
** dfs 遍历图
*/

# include <cstdio>
# include <cstring>
# include <stack>
using namespace std;

const int MAX = 100 + 2;

int g[MAX][MAX], d[MAX], f[MAX], c[MAX], n, t;

void init() {
    memset(g, 0, sizeof(g));
    memset(d, 0, sizeof(d));
    // memset(f, 0, sizeof(f));
    memset(c, 0, sizeof(c));
    scanf("%d", &n);
    int u, v, k;
    for (int i = 1; i <= n; i++) {
        scanf("%d%d", &u, &k);
        while (k--) {
            scanf("%d", &v);
            g[u][v] = 1;
        }
    }

    t = 0;
}

void dfs(int u) {
    t++;
    stack<int> s;
    s.push(u);
    int node;
    d[u] = t;
    c[u] = 1;

    while(!s.empty()) {
        t++;
        node = s.top();
        int p = 1;
        for (; p <= n; p++) {
            if (g[node][p] != 0 && c[p] == 0) {
                s.push(p);
                d[p] = t;
                c[p] = 1;
                break;
            }
        }
        if (p > n) {
            f[node] = t;
            s.pop();
        }
    }
}

void solve() {
    init();
    for (int i = 1; i <= n; i++) {
        if (c[i] == 0) {
            dfs(i);
        }
    }
    for (int i = 1; i <= n; i++) {
        printf("%d %d %d\n", i, d[i], f[i]);
    }
}

int main() {
    // freopen("infile", "r", stdin);
    // freopen("outfile", "w", stdout);
    solve();
    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
template <class A, class B> inline bool chmax(A &a, const B &b) { return b > a && (a = b, true); }
template <class A, class B> inline bool chmin(A &a, const B &b) { return b < a && (a = b, true); }
typedef long long ll;
typedef vector<int> vint;
typedef pair<int, int> pint;
typedef vector<long long> vlong;
#define _GLIBCXX_DEBUG
#define vpush(a,x) a.push_back(x);
#define rep(i, n) REP(i, 0, n)
#define all(v) v.begin(), v.end()
#define REP(i, x, n) for(int i = x; i < n; i++)
int n,tim=0;
vector<vector<int> >  lis(100000+5);
vint d(100000+5); vint f(100000+5); vector<bool> flag(100000+5);
void dfs(int now){
    if(flag[now]){
        return;
    }
    flag[now]=true;
    d[now]=++tim;
    rep(i,lis[now].size()){
        dfs(lis[now][i]);
    }
    f[now]=++tim;
}
signed main(){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cin>>n;
    int u,k,v;
    rep(i,n){
        cin>>u>>k;
        rep(j,k){
            cin>>v;
            lis[u].push_back(v);
        }
    }
    REP(i,1,n+1){
        if(!flag[i]){
            dfs(i);
        }
    }    
    REP(i,1,n+1){
        cout<<i<<' '<<d[i]<<' '<<f[i]<<'\n';
    }
    return(0);
}

C++: #include <bits/stdc++.h>
#define r(i,a,n) for(int i=a;i<n;i++)
using namespace std;
int a[101][101],start[101],end[101],n,p=0;
void dfs(int u){
	start[u]=++p;
	r(i,1,n+1)if(a[u][i])dfs(i);
	end[u]=++p;
}
int main(){
	int q,qq,qqq;
	cin>>n;
	r(i,0,n){cin>>q>>qq;
		r(i,0,qq){cin>>qqq;
			a[q][qqq]++;
		}
	}
	dfs(1);
	r(i,1,n+1)cout<<i<<' '<<start[i]<<' '<<end[i]<<endl;
}

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

vector<bool> seen;
vector<int> first_order;
vector<int> last_order;

void dfs(vector<vector<int>> &G, int v, int& ptr) {
    first_order[v] = ptr++;

    seen[v] = true;
    for(auto next_v : G[v]){
        if(seen[next_v]) continue;
        dfs(G, next_v, ptr);
    }

    last_order[v] = ptr++;
}

int main(){
    int n;
    cin >> n;
    int u;
    int k;
    vector<vector<int>> G(n);
    for (int i = 0; i < n; i++)
    {
        cin >> u >> k;
        u--;
        for (int j = 0; j < k; j++)
        {
            int a; cin >> a;
            a--;
            G[u].push_back(a);
        }
    }
    
    seen.assign(n, false);
    first_order.resize(n);
    last_order.resize(n);
    int ptr = 1;
    for(int i = 0; i < n; i ++){
        if(!seen[i]) dfs(G, i, ptr);
    }

    for (int v = 0; v < n; v++)
        cout << v + 1 << " " << first_order[v] << " " << last_order[v] << endl;
}