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 <iostream>
using namespace std;

static const int N = 100;
int n,color[N],M[N][N],d[N],f[N];
int t;

void dfs_visit(int u){
  int v;
  color[u] = 1;
  d[u] = ++t;
  for (v = 0; v < n; v++) {
    if(M[u][v] == 0) continue;
    if(color[v] == 0) dfs_visit(v);
  }
  color[u] = 2;
  f[u] = ++t;
}
void dfs(){
  int u;

  for (u = 0; u < n; u++) {
    color[u] = 0;
  }
  t = 0;

  for (u = 0; u < n; u++) {
    if(color[u] == 0) dfs_visit(u);
  }

  for (u = 0; u < n; u++) {
    cout << u+1 << " " << d[u] << " "<< f[u] << endl;
  }
}

int main() {
  int i,j,u,k,v;

  cin >> n;
  for (i = 0; i < n; i++) {
    for (j = 0; j < n; j++) {
      M[i][j] = 0;
    }
  }
  for (i = 0; i < n; i++) {
    cin >> u >> k;
    u--;
    for (j = 0; j < k; j++) {
      cin >> v;
      v--;
      M[u][v] = 1;
    }
  }
  //cout << "done1" << endl;

  dfs();

  return 0;
}

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

int main() {
    int n;
    cin>>n;
    vector<vector<int> > arr(n);
    vector<int> tmparr;
    int u, k;
    int tmp;
    for(int i=0;i<n;++i){
        cin>>u>>k;
        u--;
        tmparr.clear();
        for(int j=0;j<k;++j){
            cin>>tmp;
            tmp--;
            tmparr.push_back(tmp);
        }
        arr[u] = tmparr;
    }
    stack<int> stack;
    stack.push(0);
    map<int, int> used;
    map<int, int> owari;
    map<int, pair<int, int> > ans;
    int state;
    int time = 1;
    while(!stack.empty()){
        while(!stack.empty()){
            state = stack.top();
            if(used[state]>0){
                if(owari[state]==0){
                    ans[state].second = time;
                    owari[state]++;
                    time++;
                }
                stack.pop();
            }
            else {
                ans[state].first = time;
                time++;
            }
            used[state]++;
            for(int i=arr[state].size()-1;i>=0;--i){
                if(used[arr[state][i]]==0){
                    stack.push(arr[state][i]);
                }
            }
        }
        for(int i=0;i<n;++i){
            if(used[i]==0){
                stack.push(i);
                break;
            }
        }
    }
    for(int i=0;i<n;++i){
        cout<<i+1<<" "<<ans[i].first<<" "<<ans[i].second<<endl;
    }
}

C++: #include <cstdio>

typedef struct vertex_{
    int found;
    int d;
    int f;
}vertex;

int search(vertex *array, int (*A)[101], int id, int n, int time){
    if(array[id].found)return time;
    array[id].found=1;
    array[id].d=++time;
    for(int i=1;i<=n;i++){
        if(A[id][i])time=search(array,A,i,n,time);
    }
    array[id].f=++time;
    return time;
}

int searchAll(vertex *array, int (*A)[101], int n){
    int time = 0;
    for(int id=1;id<=n;id++){
        if(!array[id].found){
            time=search(array,A,id,n,time);
            printf("%d\n",time);
        }
    }
    return time;
}

int main(){
    int i, j, n, u, k, v;
    scanf("%d",&n);
    vertex array[n+1];
    for(i=1;i<=n;i++)array[i].found=0;
    int A[101][101];
    for(i=1;i<=n;i++){
        for(j=1;j<=n;j++){
            A[i][j]=0;
        }
    }
    for(i=1;i<=n;i++){
        scanf("%d %d",&u,&k);
        for(j=0;j<k;j++){
            scanf("%d",&v);
            A[u][v]=1;
        }
    }
    int time = searchAll(array, A, n);
    for(i=1;i<=n;i++)printf("%d %d %d\n",i,array[i].d,array[i].f);
    return 0;
}

C++: #include <algorithm>
#include <iostream>
#include <vector>
#include <math.h>
#include <set>
#include <map>
#include <string>
#include <stack>
#include <queue>
#include <iomanip>
#include <numeric>
#include <tuple>
#define _USE_MATH_DEFINES
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> plglg;
typedef tuple<int, int, int> tiii;
typedef tuple<ll, ll, ll> tlglglg;
double pi = 3.141592653589793;
ll mod = 1000000007;
int intmax = 2147483647;
int intmin = -2147483648;
ll llmax = 9223372036854775807;
ll llmin = -9223372036854775807;

struct edge {
    int to, cost;
};

int V;
vector<int> G[1000000];
int st[1000000];
int en[1000000];
int t;

void DFS(int n) {
    t++;
    st[n] = t;
    int s = G[n].size();
    for (int i = 0; i < s; i++) {
        if (st[G[n][i]] == intmax) {
            DFS(G[n][i]);
        }
    }
    t++;
    en[n] = t;
}

int main() {
    int N;
    cin >> N;
    V = N;
    fill(st, st + V + 10, intmax);
    fill(en, en + V + 10, intmax);
    t = 0;
    for (int i = 0; i < N; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int n;
            cin >> n;
            G[i].push_back(n - 1);
        }
    }
    for (int i = 0; i < N; i++) {
        if (st[i] == intmax) {
            DFS(i);
        }
    }
    for (int i = 0; i < N; i++) {
        cout << i + 1 << " " << st[i] << " " << en[i] << endl;
    }
}