Go: package main

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

// repr state of visited node
// WHITE yet visit
// GEAY  visiting
// BLACK visited
const (
	WHITE int = iota
	GRAY
	BLACK
)

type dfsGraph struct {
	g      [][]int
	colors []int
	stime  []int // Start time of visiting node
	ftime  []int // Finish time of visiting node
}

var time int

func makeAdjList() [][]int {
	var n int
	fmt.Scanf("%d", &n)

	adj := make([][]int, n)
	for i := 0; i < n; i++ {
		adj[i] = make([]int, n)
	}

	sc := bufio.NewScanner(os.Stdin)
	for i := 0; i < n; i++ {
		sc.Scan()
		nodeInfo := strings.Split(sc.Text(), " ")
		outDegree, _ := strconv.Atoi(nodeInfo[1])

		if outDegree > 0 {
			for k := 0; k < outDegree; k++ {
				j, _ := strconv.Atoi(nodeInfo[k+2])
				j-- // convert 1 based to 0 based
				adj[i][j] = 1
			}
		}
	}

	return adj
}

func (dg dfsGraph) dfsVisit(u int) {
	// 頂点uを訪問中に設定
	dg.colors[u] = GRAY
	time++
	dg.stime[u] = time

	// uの隣接nodeを訪問
	for v := 0; v < len(dg.g); v++ {
		if dg.g[u][v] == 0 {
			continue // 辺がなければスキップ
		}

		// vが未訪問なら訪問
		if dg.colors[v] == WHITE {
			dg.dfsVisit(v)
		}
	}

	// 頂点uを訪問済みに設定
	dg.colors[u] = BLACK
	time++
	dg.ftime[u] = time
}

func (dg dfsGraph) dfs() {
	for i := 0; i < len(dg.g); i++ {
		if dg.colors[i] == WHITE {
			dg.dfsVisit(i)
		}
	}
}

func (dg dfsGraph) printDfsTime() {
	for i := 0; i < len(dg.g); i++ {
		fmt.Printf("%d %d %d\n", i+1, dg.stime[i], dg.ftime[i])
	}
}

func main() {
	adj := makeAdjList()
	colors := make([]int, len(adj))
	stime := make([]int, len(adj))
	ftime := make([]int, len(adj))
	graph := dfsGraph{adj, colors, stime, ftime}
	graph.dfs()
	graph.printDfsTime()
}

C++: #define _USE_MATH_DEFINES
#include<stdio.h>
#include<string>
#include<iostream>
#include<cctype>
#include<cstdio>
#include<vector>
#include<stack>
#include <algorithm>
#include<math.h>
#include<set>
#include<map>
#include<iomanip>

//#include<bits/stdc++.h>



using namespace std;




int main() {
	
	int n;
	cin>>n;
	vector<vector<int>>t(n,vector<int>(n));
	for(int i=0;i<n;i++){
		int x,r;cin>>r>>x;
		for(int j=0;j<x;j++){
			int w;cin>>w;w--;t[i].push_back(w);
		}
		sort(t[i].begin(),t[i].end());
	}
	stack<int>S;
	bool F[105]={};
	S.push(0);
	int p=1;
	F[0]=1;
	vector<int>G(n),H(n);
	int g=1;
	G[0]=1;
	while(S.size()){
		g++;
		int v=S.top();
		int a=-1;
		for(int i=0;i<t[v].size();i++){
			if(!F[t[v][i]]){
				a=t[v][i];break;
			}
		}
		if(a==-1){
			H[S.top()]=g;
			S.pop();
		}
		else{
			F[a]=1;
			G[a]=g;
			S.push(a);
		}
	}
	for(int i=0;i<n;i++){
		cout<<i+1<<" "<<G[i]<<" "<<H[i]<<endl;
	}
	

	
	return 0;
}

C++: #include<stdio.h>
#include<stack>
using namespace std;

enum Color{
    WHITE,
    GRAY,
    BLACK
};

int n;
bool M[100][100];   //隣接行列
int nt[100];    //next用
stack<int> S;           //深さ優先探索のスタック
Color color[100];   //各頂点の訪問状態

int d[100]; //この問題
int f[100]; //この問題
int time = 1;

int next(int u){
    for(int v=nt[u]; v<n; v++){ //点を進めていく
        nt[u] = v+1;
        if(M[u][v]) return v;   //辺があれば
    }
    return -1;
}

void dfs(int i){
    S.push(i);
    color[i] = GRAY;
    d[i] = time++;

    while(!S.empty()){
        int u=S.top();
        int v=next(u);  //隣接している頂点を順番に取得
        if(v!=-1){
            if(color[v]==WHITE){
                color[v] = GRAY;
                d[v] = time++;
                S.push(v);
            }
        }else{
            S.pop();
            color[u] = BLACK;
            f[u] = time++;
        }
    }

}

void dfs_init(){
    for(int i=0; i<n; i++){
        color[i] = WHITE;
        nt[i] = 0;
    }
    for(int i=0; i<n; i++){
    if(color[i]==WHITE) dfs(i); //スタート地点
    }

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

int main(){

    scanf("%d", &n);

    for(int i=0; i<n; i++){
        int u, k;
        scanf("%d %d", &u, &k);
        u--;
        for(int j=0; j<k; j++){
            int v;
            scanf("%d", &v);
            v--;
            M[u][v] = true;    //辺を引く
        }
    }

    dfs_init();

    return 0;
}

C++: #include <iostream>

using namespace std;

int graph[101][101]={};
int d[101]={};
int f[101]={};
int n,v,k,time1 = 0,sw[101] = {};


void dfs1(int u){

  sw[u] = 1;
  d[u] = ++time1;

  for(int i = 1; i <= n; i++){
    if( graph[u][i] == 1 && sw[i] == 0 ){
     dfs1(i);
    }

  }
    f[u] = ++time1;
}


int main(){
  int u;
  cin >> n ;
  //グラフをつくる
  for(int i = 0; i < n; i++){
    cin >> u >> k ;
    for(int j = 0; j < k ; j++){
      cin >> v;
      graph[u][v] = 1;
    }
  }

  dfs1(1);

  for(int i = 1; i <= n; i++ ){
    cout << i << ' ' <<  d[i]<< ' ' << f[i] << endl;

  }
}

C++: #include <stdio.h>

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

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

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 <bits/stdc++.h>
#define REP(i,n) for (int i=0;i<(n);i++)
#define All(v) (v).begin(),(v).end()
#define mp(a,b) make_pair(a,b)
#define pb(a) push_back(a)
using namespace std;
typedef long long llint;
typedef pair<int, int> P;
const int MOD = (int)1e9 + 7;
const int INF = 999999999;

int N;
int tt = 0;
vector< vector<int> > G;
vector<int> H, d, f;
int itrNum[100001];
stack<int> S;

void dfs(int u){
    S.push(u);
    H[u] = 0;

    while(!S.empty()){
        u = S.top();  // ?¨????????????????
        if(d[u] == 0) d[u] = ++tt;
        auto itr_v = next(G[u].begin(), itrNum[u]);
        if(itr_v != G[u].end()){
            itrNum[u]++;
            int v = *itr_v;
            if(H[v] == -1){
                H[v] = 0;
                S.push(v);
            }
        }else{
            S.pop();
            H[u] = 1;
            f[u] = ++tt;
        }
    }
}

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

    cin >> N;
    G = vector<vector<int> >(N);
    H = vector<int>(N, -1);
    d = vector<int>(N, 0);
    f = vector<int>(N, 0);
    memset(itrNum, 0, sizeof(itrNum));
    REP(i, N){
        int u,k;
        cin >> u >> k;
        u--;
        REP(j ,k){
            int v;
            cin >> v;
            v--;
            G[u].pb(v);
        }
    }

    REP(i, N) if(H[i] == -1) dfs(i);
    REP(i, N){
        cout << i+1 << " " << d[i] << " " << f[i] << "\n";
    }
    return 0;
}

C++: #include <iostream>
#include <vector>

using namespace std;

void dfs(int n, vector<vector<int> > &G, int s, int *d, int *f, int &t) {
    d[s] = t++;
    for (int i = 0; i < G[s].size(); i++) {
        int v = G[s][i];
        
        if (d[v] != -1)
            continue;

        dfs(n, G, v, d, f, t);
    }
    f[s] = t++;
}

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

    int *f = new int[n], *d = new int[n];
    for (int i = 0; i < n; i++)
        f[i] = d[i] = -1;

    int t = 1;
    for (int i = 0; i < n; i++) {
        if (d[i] == -1)
            dfs(n, G, i, d, f, t);
    }

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

    return 0;
}