Go: package main

/*
深さ優先探索
*/

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

func main() {
	scanner := makeScanner(8192)
	n := eGetInt(scanner)
	g := make([][]int, n+1)
	for i := 1; i < n+1; i++ {
		ints := eGetInts(scanner)
		num, vcount := ints[0], ints[1]
		g[i] = make([]int, vcount)
		for j := 0; j < vcount; j++ {
			g[num][j] = ints[j+2]
		}
	}
	hist := make([]struct{ d, f int }, n+1)
	t := 0
	var visit func(int)
	visit = func(num int) {
		if hist[num].d == 0 {
			stack := []int{}
			t++
			hist[num].d = t
			stack = append(stack, num)
			for len(stack) > 0 {
				// トップを訪問する
				top := stack[len(stack)-1]
				for i := 0; i < len(g[top]); i++ {
					if hist[g[top][i]].d == 0 {
						t++
						hist[g[top][i]].d = t
						stack = append(stack, g[top][i])
						goto endloop
					}
				}
				// 訪問場所がなくなったら
				// pop
				stack = stack[0 : len(stack)-1]
				t++
				hist[top].f = t
			endloop:
			}
		}
	}
	for i := 1; i < n+1; i++ {
		visit(i)
	}
	for i := 1; i < n+1; i++ {
		fmt.Println(i, hist[i].d, hist[i].f)
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetInt64(r *bufio.Scanner) int64 {
	line := eGetLine(r)
	return eAtoInt64(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetInt64s(r *bufio.Scanner) []int64 {
	fields := eGetFields(r)
	ints := make([]int64, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoInt64(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}
func eAtoInt64(s string) int64 {
	n, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

C++: #include<iostream>
int main(){

  int n,a;
  std::cin>>n;

  int Adj[100][100],adj[100][100]={0},find[100][2],back[100][100],depth[100]={0},endflag[100]={0},flag;
	int u[n],k[n],kcou=0,timenow=0,v,pred,prev,firstv,backcount[100]={0},flag1=0;
  for(int i=0;i<n;i++){
    std::cin>>u[i];
    std::cin>>k[i];
    for(int j=0;j<k[i];j++){
      std::cin>>Adj[i][j];
    }
  }
	
	/*
  for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
    	std::cout<<Adj[i][j]<<" ";
    }
  	std::cout<<"\n";
  }*/
	
	v=0;
	firstv=0;
	while(timenow<n*2){
		flag=0;
		if(find[firstv][0]!=NULL&&find[firstv][1]!=NULL){
			for(int i=0;i<n;i++){
				if(find[i][0]==NULL){
					//std::cout<<i<<"\n";
					firstv=i;
					v=i;
					break;
				}
			}
		}
		
		// std::cout<<"v="<<v+1<<" ";
		//std::cout<<find[v][0]<<" "<<find[v][1];
		// std::cout<<" endflag="<<endflag[v]<<" ";
		if(find[v][0]==NULL){
			timenow++;
			find[v][0]=timenow;
			// std::cout<<v+1<<"[0]= '"<<timenow<<"' ";
			flag=1;
			//std::cout<<flag<<" 1";
		}else if(find[v][1]==NULL){
			if(endflag[v]==1){
				if(backcount[v]<=1){
				timenow++;
				find[v][1]=timenow;
				// std::cout<<v+1<<"[1]= '"<<timenow<<"' ";
				}
				flag=2;
			}
			//std::cout<<flag;
		}else{
			backcount[v]--;
			v=back[v][backcount[v]];
			//backcount[v]--;
			flag=3;
			//std::cout<<flag<<" 0";
		}

		if(flag==0){
				pred=depth[v];
				depth[v]++;
				prev=v;
				v=Adj[v][pred]-1;
				back[v][backcount[v]]=prev;
				backcount[v]++;
				//std::cout<<flag<<"\n";
		}else if(flag==1){
			if(endflag[v]==0){
				if(Adj[v][depth[v]]-1!=v){
					while(find[Adj[v][depth[v]]-1][0]!=NULL && k[v]-1!=depth[v]){
						depth[v]++;
					}
					if(find[Adj[v][depth[v]]-1][0]==NULL){
						pred=depth[v];
						depth[v]++;
						prev=v;
						v=Adj[v][pred]-1;
						back[v][backcount[v]]=prev;
						backcount[v]++;
					}else{
						depth[v]++;
					}
				}else{
					pred=depth[v];
					depth[v]++;
				}
			}
		}else if(flag==2){
			backcount[v]--;
			v=back[v][backcount[v]];
			//backcount[v]--;
			//std::cout<<flag<<"\n";
		}
		if(depth[v]>k[v]-1){
			endflag[v]=1;
		}
		// std::cout<<"flag="<<flag<<"\n";
	}
	
	
	
	
  for(int i=0;i<n;i++){
     std::cout<<i+1<<" "<<find[i][0]<<" ";
     std::cout<<find[i][1]<<"\n";
    //std::cout<<"\n";
  }

  return 0;
}

C++: #include <bits/stdc++.h>
#define rep(i, to) for (int i = 0; i < (to); i++)
#define rrep(i, to) for (int i = (to) - 1; i >= 0; i--)
#define repf(i, from, to) for (int i = (from); i < (to); i++)
#define all(v) v.begin(), v.end()
#define unless(cond) if (!(cond))
using namespace std;
using ll = long long;
template <typename T>
using V = vector<T>;
template <typename T, typename U>
using P = pair<T, U>;

int main() {
  int n;
  V<V<int>> graph;
  cin >> n;
  graph.resize(n);

  rep(i, n) {
    int u, k;
    cin >> u >> k;
    graph[u - 1].resize(k);

    rep(j, k) {
      cin >> graph[u - 1][j];
      graph[u - 1][j]--;
    }
  }

  stack<int> way;

  V<bool> visited(n, false);
  V<int> arrived_t(n, 0);
  V<int> finished_t(n, 0);

  int t = 0;
  rep(i, n) {
    if(visited[i]) {
      continue;
    }
    visited[i] = true;
    arrived_t[i] = ++t;
    way.push(i);

    while(!way.empty()) {
      int current_i = way.top();

      int next_i = -1;
      rep(i, graph[current_i].size()) {
        int tmp_next_i = graph[current_i][i];
        if(!visited[tmp_next_i]) {
          next_i = tmp_next_i;
          break;
        }
      }

      t++;
      if(next_i != -1) {
        visited[next_i] = true;
        arrived_t[next_i] = t;
        way.push(next_i);
      } else {
        way.pop();
        finished_t[current_i] = t;
      }
    }
  }


  rep(i, n) {
    cout << i + 1 << " " << arrived_t[i] << " " << finished_t[i] << endl;;
  }

}

C++: #include <vector>
#include <iostream>
using namespace std;
int n, u, k, v, t, d[100][2]; vector<int> g[100];
void rec(int pos) {
	for(int i = 0; i < g[pos].size(); i++) {
		if(!d[g[pos][i]][0]) {
			d[g[pos][i]][0] = ++t;
			rec(g[pos][i]);
			d[g[pos][i]][1] = ++t;
		}
	}
}
int main() {
	cin >> n;
	for(int i = 0; i < n; i++) {
		cin >> u >> k;
		for(int j = 0; j < k; j++) cin >> v, g[u - 1].push_back(v - 1);
	}
	rec(0);
	for(int i = 0; i < n; i++) cout << i + 1 << ' ' << d[i][0] << ' ' << d[i][1] << endl;
}