Go: package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

const N = 100

const (
	WHITE = iota
	GRAY
	BLACK
)

type Graph struct {
	M               [N][N]int
	color, d, f, nt [N]int
	tt              int
}

func (g *Graph) next(u, n int) int {
	for v := g.nt[u]; v < n; v++ {
		g.nt[u] = v + 1
		if g.M[u][v] != 0 {
			return v
		}
	}
	return -1
}

func (g *Graph) dfsVisit(r, n int) {
	var S []int
	S = append([]int{r}, S...)
	g.color[r] = GRAY
	g.tt++
	g.d[r] = g.tt

	for len(S) != 0 {
		u := S[0]
		v := g.next(u, n)
		if v == -1 {
			S = S[1:]
			g.color[u] = BLACK
			g.tt++
			g.f[u] = g.tt
			continue
		}

		if g.color[v] != WHITE {
			continue
		}

		g.color[v] = GRAY
		g.tt++
		g.d[v] = g.tt
		S = append([]int{v}, S...)
	}
}

func (g *Graph) dfs(n int) string {
	for i := 0; i < n; i++ {
		g.color[i] = WHITE
	}
	g.tt = 0

	for u := 0; u < n; u++ {
		if g.color[u] == WHITE {
			g.dfsVisit(u, n)
		}
	}

	var out bytes.Buffer
	for i := 0; i < n; i++ {
		out.WriteString(fmt.Sprintf("%d %d %d\n", i+1, g.d[i], g.f[i]))
	}

	return strings.TrimRight(out.String(), "\n")
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	var g Graph
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		u--
		for j := 0; j < k; j++ {
			sc.Scan()
			v, _ := strconv.Atoi(sc.Text())
			v--
			g.M[u][v] = 1
		}
	}

	return g.dfs(n)
}

func main() {
	fmt.Println(answer(os.Stdin))
}

C++: #include<iostream>
#include<vector>
using namespace std;
vector<vector<int>> G(100);
vector<pair<int,int>> D(100);
bool visited[100];
int elapse = 1;
void dfs(int x){
    if(visited[x]) return;
    visited[x] = true;
    D[x].first = elapse;
    elapse++;
    for(auto &a:G[x]) dfs(a);
    D[x].second = elapse;
    elapse++;
}
int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    int N;
    cin>>N;
    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].push_back(--v);
        }
    }
    for(int i=0;i<N;++i) dfs(i);
    for(int i=0;i<N;++i) cout<<i+1<<' '<<D[i].first<<' '<<D[i].second<<endl;
}

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


#define INF 1000000000000
int n;
vector<int>d(101);
vector<int>f(101);
vector<vector<int>>g(101,vector<int>(0));
int tim=1;
void dfs(int x){
      if(!d[x]){d[x]=tim;tim++;}
      if(!g[x].size()&& !f[x]){f[x]=tim; tim++;}
  rep(i,g[x].size()){
    if(!d[g[x][i]])dfs(g[x][i]);
    if(i==g[x].size()-1&& !f[x]){f[x]=tim;tim++;}
  }
}
int restart=0;
bool owari(vector<int>l){
  rep(i,n){
    if(l[i+1]==0){return false;}
  }
  return true;
}
signed main() {

   cin>>n;
   rep(i,n){
     int t,m;cin>>t>>m;
     rep(j,m){int k; cin>>k; if(k!=i+1){g[i+1].push_back(k);}}
   }

   while(!owari(d)){
     int restart=0;
     rep(i,n){if(d[i+1]==0){restart=i+1;break;}}
     dfs(restart);
   }
   rep(i,n){
     cout<<i+1<<' '<<d[i+1]<<' '<<f[i+1]<<endl;
   }
}

C++: #include <cstdio>
#include <stack>
using namespace std;

#define start first
#define end second

static const int NOT   = false;
static const int WHITE = 1;
static const int GRAY  = 2;
static const int BLACK = 3;
static const int N	   = 101;

int  n;
int  VisitedInfo[N];
bool Graph[N][N];
pair< int, int > Time[N];

void dfs( int u );
int  nextNode( int u );

int main()
{

	int u, k, v;

	for( int i = 0; i < N; i++ ) {
		for( int j = 0; j < N; j++ ) Graph[i][j] = NOT;
		VisitedInfo[i] = WHITE;
	}

	scanf( "%d", &n );
	for( int i = 0; i < n; i++ ) {
		
		scanf( "%d %d", &u, &k );
		for( int j = 0; j < k; j++ ) {

			scanf( "%d", &v );
			Graph[u][v] = true;

		}

	}

	dfs( 1 );

	for( int i = 1; i <= n; i++ ) printf( "%d %d %d\n", i, Time[i].start, Time[i].end );

	return 0;

}

void dfs( int u )
{

	int time = 1;
	stack< int > dfsInfo;

	dfsInfo.push( u );
	Time[u].start  = time;
	VisitedInfo[u] = GRAY;

	while( !dfsInfo.empty() ) {

		int ppos = dfsInfo.top();
		int pos  = nextNode( ppos );

		if( pos != 0 ) {
			if( VisitedInfo[pos] == WHITE ) {

				dfsInfo.push( pos );
				Time[pos].start  = ++time;
				VisitedInfo[pos] = GRAY;

			}
		}
		if( pos == 0 && VisitedInfo[ppos] != WHITE ){

			dfsInfo.pop();
			Time[ppos].end	  = ++time;
			VisitedInfo[ppos] = BLACK;

		}

	}

}

int nextNode( int now )
{

	for( int i = 1; i <= n; i++ ) {
		if( Graph[now][i] && VisitedInfo[i] == WHITE ) return i;
	}

	return 0;

}

C++: #include <iostream>
#include <vector>
#include <queue>
#include <string>
#include <algorithm>
#include <utility>
#include <climits>
#include <cstring>
#include <cstdio>

using namespace std;
typedef long long int llg;

const int INF = 1000001000;
#define REP(var, count) for(int var=0; var<count; var++)

template <typename T>
using reverse_queue = std::priority_queue<T, std::vector<T>, std::greater<T> >;

template<typename A, size_t N, typename T>
void Fill(A (&array)[N], const T &val){
	std::fill( (T*)array, (T*)(array+N), val );
}

vector<int> rin[105];
pair<int, int> res[105];

int bfs(int a, int time) {
	res[a].first = time;
	for ( int r : rin[a] ) {
		if ( res[r].first != -1 ) { continue; }
		time = bfs(r, time + 1);
	}
	res[a].second = time + 1;
	return res[a].second;
}

int main(void) {
	int N;
	cin >> N;
	
	for(int i=1; i<=N; i++) {
		res[i].first = -1;
		res[i].second = -1;
		
		int U, K;
		cin >> U >> K;
		REP(j, K) {
			int x;
			cin >> x;
			rin[U].push_back(x);
		}
	}
	
	bfs(1, 1);
	
	for(int i=1; i<=N; i++) {
		printf("%d %d %d\n", i, res[i].first, res[i].second);
	}
}

C++: #include<bits/stdc++.h>
#define rep(i,n) for(int i = 0;i<n;i++)
using namespace std;
typedef pair<int,int> P;
typedef long long ll;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0;}
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0;}

int n; //頂点数
vector<vector<int> > g;//グラフ
vector<int>d;//到着時刻を記録
vector<int>f;//終了時刻を記録
void dfs(int v,int& i) {
    if(d[v] == 0) {
        i++;
        d[v] = i;//到着時刻を記録
    }    
    
    for(int next_v : g[v]) {
        if(d[next_v]) continue;//訪問済みなら飛ばす
        dfs(next_v,i);//隣接頂点について探索
    }
    if(f[v] == 0) {
        i++;
        f[v] = i;//終了時刻を記録
    }
}
int main() {
    cin >> n;
    //nで初期化
    g.resize(n);
    f.resize(n);
    d.resize(n);
    rep(i,n) {
        int u; //頂点番号
        cin >> u;
        u--;
        int k; //出次数
        cin >> k;
        rep(j,k) {
            int v;//隣接する頂点
            cin >> v;
            v--;
            g[u].push_back(v);
        }
    }
    int count = 0;
    //各頂点からdfs
    for(int i = 0;i<n;i++) {
        dfs(i,count);
    }    
    //各頂点について到着時刻と終了時刻を出力
    for(int i = 0;i<n;i++) {
        cout << i+1 << " " << d[i] << " " << f[i] << endl;
    }
    return 0;
}