Go: package main

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

/***************************************************************
stackによる深さ優先探索を実装する。
***************************************************************/

const (
	N     = 100
	WHITE = 0
	GRAY  = 1
	BLACK = 2
)

var (
	n            int
	Adj          [N][N]int
	statusColor  [N]int
	discoverTime [N]int
	finishTime   [N]int
	clock        int
	nt           [N]int
)

/***************************************************************
Stackの定義:
- field
	container: ノードの格納されたスライス
	sp: スタックポインタ
- method
	size(): スタックに積まれているノードの個数を返す
	top(): スタックの一番上に積まれているノードを返す
	isEmpty(): スタックが空かどうかを返す
	pop(): スタックの要素をポップし削除する
	push(): スタックに要素を積む
***************************************************************/

type Stack struct {
	container []int
	sp        int
}

func (s *Stack) size() int {
	return len(s.container)
}

func (s *Stack) top() int {
	return s.container[s.sp]
}

func (s *Stack) isEmpty() bool {
	return s.sp == 0
}

func (s *Stack) pop() int {
	_pop := func() {
		s.container = s.container[:len(s.container)-1]
	}
	defer _pop()
	if s.isEmpty() {
		panic("There is no elements in stack!")
	}
	s.sp--
	return s.container[s.sp]
}

func (s *Stack) push(n int) {
	s.sp++
	s.container[s.sp] = n
}

func next(u int) int {
	for v := nt[u]; v < n; v++ {
		nt[u] = v + 1
		if Adj[u][v] == 1 {
			return v
		}
	}
	return -1
}

func _DFS(target int) {
	for i := 0; i < n; i++ {
		nt[i] = 0
	}
	stack := new(Stack)
	stack.container = make([]int, N+1)
	stack.push(target)
	statusColor[target] = GRAY
	clock++
	discoverTime[target] = clock
	for !stack.isEmpty() {
		u := stack.top()
		v := next(u)
		if v != -1 {
			if statusColor[v] == WHITE {
				statusColor[v] = GRAY
				clock++
				discoverTime[v] = clock
				stack.push(v)
			}
		} else {
			stack.pop()
			statusColor[u] = BLACK
			clock++
			finishTime[u] = clock
		}
	}
}

func DFS() {
	for i := 0; i < n; i++ {
		statusColor[i] = WHITE
		nt[i] = 0
	}
	clock = 0
	for i := 0; i < n; i++ {
		if statusColor[i] == WHITE {
			_DFS(i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, discoverTime[i], finishTime[i])
	}
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			Adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ := strconv.Atoi(scanner.Text())
		scanner.Scan()
		k, _ := strconv.Atoi(scanner.Text())
		u--
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ := strconv.Atoi(scanner.Text())
			v--
			Adj[u][v] = 1
		}
	}

	DFS()
}

C++: #include "bits/stdc++.h"

using namespace std;

using ll = long long;

template<typename T> using V = std::vector<T>;
using Vi = V<int>;
using VVi = V<V<int>>;
using Vl = V<ll>;
using VVl = V<V<ll>>;
using Vs = V<string>;

template<typename T1, typename T2> using P = std::pair<T1, T2>;
using Pii = P<int, int>;
using Pll = P<ll, ll>;
using Pdd = P<double, double>;

template<typename T1, typename T2> using M = std::map<T1, T2>;
using Mii = M<int, int>;
using Msi = M<string, int>;

#define REP(i,n) for(int i=0;i<(int)(n);++i)
#define REP2(i,s,e) for(int i=(int)(s);i<(int)(e);++i)
#define RREP(i,s,e) for(int i=(int)(s);i>=(int)(e);--i)
#define FOR(i,c) for(__typeof((c).begin())i=(c).begin(),ie=(c).end();i!=ie;++i)
#define ALL(c) (c).begin(), (c).end()

const double PI = acos(-1);
const ll MOD = 1e9+7;

int n;
string s;

int main() {
    cin >> n;

    VVi edges(n);
    REP(i, n) {
        int u, k;
        cin >> u >> k;
        u--;
        REP(j, k) {
            int v; cin >> v;
            v--;
            edges[u].push_back(v);
        }
    }

    Vi find(n, -1), end(n, -1);
    stack<int> s;
    s.push(0);
    int time = 1;
    while (true) {
        while (!s.empty()) {
            int node = s.top();
            if (find[node] == -1) {
                find[node] = time;
                time++;
            } else {
                if (end[node] == -1) {
                    end[node] = time;
                    time++;
                }
                s.pop();
                continue;
            }
            RREP(i, edges[node].size()-1, 0) {
                int v = edges[node][i];
                if (find[v] == -1) {
                    s.push(v);
                }
            }
        }
        int idx = -1;
        REP(i, n) if (find[i] == -1) {
            idx = i;
            break;
        }
        if (idx == -1) {
            break;
        }
        s.push(idx);
    }

    REP(i, n) {
        printf("%d %d %d\n", i+1, find[i], end[i]);
    }

    return 0;
}

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,oya[100][100],oyacou[100]={0};
	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+1<<" ";
		//std::cout<<find[v][0]<<" "<<find[v][1];
		
		if(find[v][0]==NULL){
			timenow++;
			find[v][0]=timenow;
			std::cout<<" '"<<timenow<<"' ";
			flag=1;
			//std::cout<<flag<<" 1";
		}else if(find[v][1]==NULL){
			if(v==7){
				//std::cout<<endflag[v];
				//std::cout<<backcount[v];
			}
			if(endflag[v]==1){
				if(backcount[v]<=1){
				timenow++;
				find[v][1]=timenow;
				//std::cout<<" '"<<timenow<<"' ";
				}
				flag=2;
			}
			//std::cout<<flag<<" 2";
		}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){
				flag1=0;
				if(Adj[v][depth[v]]-1!=v){
					for(int i=0;i<oyacou[v];i++){
						if(Adj[v][depth[v]]-1==oya[v][i]){
							flag1=1;
						}
					}
					if(flag1==0){
						pred=depth[v];
						depth[v]++;
						prev=v;
						v=Adj[v][pred]-1;
						back[v][backcount[v]]=prev;
						backcount[v]++;
						for(int i=0;i<oyacou[pred];i++){
							oya[v][i]=oya[prev][i];
							oyacou[v]++;
						}
						oya[v][oyacou[v]]=prev;
						oyacou[v]++;
						//std::cout<<v<<"\n";
						for(int i=0;i<oyacou[v];i++){
							std::cout<<"("<<oya[v][oyacou[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;
		}
		
	}
	
	
	
	
  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;
}