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;

#define FOR(i,s,e) for((i)=(s);(i)<(int)(e);(i)++)
#define REP(i,e) FOR(i,0,e)

#define all(o) (o).begin(), (o).end()
#define psb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))

typedef long long ll;
typedef pair<int, int> PII;

const double EPS = 1e-10;

typedef struct edge_def {
  int from;
  int to;
  int cost;

  edge_def(int _from, int _to, int _cost) {
    from = _from;
    to   = _to;
    cost = _cost;
  }
} edge;

const int V = 100;
int n, t;
vector<edge> es[V];
int d[V], f[V];

void dfs(int v) {
  int i;
  d[v] = ++t;
  for (i=0; i<(int)es[v].size(); i++) {
    int to = es[v][i].to;
    if (d[to] == -1) dfs(to);
  }
  f[v] = ++t;
}

int main() {
  int i, j;
  memset(d, 0xff, sizeof(d));
  memset(f, 0, sizeof(f));
  for (i=0; i<V; i++) es[i].clear();

  scanf("%d ", &n);
  for (i=0; i<n; i++) {
    int u, v, k;
    scanf("%d ", &u);
    scanf("%d ", &k);
    for (j=0; j<k; j++) {
      scanf("%d ", &v);
      es[u-1].psb(edge(u-1, v-1, 0));
    }
  }

  t = 0;
  dfs(0);

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

	return 0;
}

C++: #include <iostream>
#include <stdio.h>
#include <cstring>
#include <math.h>
#include <algorithm>
#include <vector>
#include <string>
#include <stdlib.h>
#include <queue>
#include <stack>
#include <utility>
#define rep(i,n) for(int i=0;i<n;i++)
#define rrep(i,n) for(int i=n-1;i>=0;i--)
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define ll long long
#define INF 1000000001
#define mod 1000000007
using namespace std;
int dfs(int n,int x,vector<int> k,vector<vector<int>> v,vector<int> &a,vector<int> &b,int &count);


int main(){
	int n;
	cin>>n;
	vector<vector<int> > v(n);
	vector<int> k(n);
	int x;
	rep(i,n){
		cin>>x;
		cin>>k[i];
		v[i].resize(k[i]);
		rep(j,k[i]){
			cin>>v[i][j];
			v[i][j]--;
		}
	}
	vector<int> a(n),b(n);
	int count=1;
	a[0]=1;
	dfs(n,0,k,v,a,b,count);

	rep(i,n){
		if(a[i]==0){
			dfs(n,i,k,v,a,b,count);
		}
	}


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

	return 0;
}
int dfs(int n,int x,vector<int> k,vector<vector<int>> v,vector<int> &a,vector<int> &b,int &count){
	/*if(k[x]==0){
		count++;
		a[x]=count;
	}*/
	rep(i,k[x]){
		if(a[v[x][i]]==0){
			count++;
			a[v[x][i]]=count;
			dfs(n,v[x][i],k,v,a,b,count);
		}
		if(i==k[x]-1){
			k[x]=0;
		}
	}
	if(k[x]==0){
		count++;
		b[x]=count;
	}
	return 0;
}

C++: #include<iostream>
#include<cstring>
using namespace std;

const int maxn=110;
int table[maxn][maxn],vis[maxn];
int d[maxn],f[maxn];
int n,tt;

void dfs(int v){
    d[v]=++tt;
    vis[v]=1;
    for(int i=1;i<=n;i++){
        if(!vis[i] && table[v][i])
            dfs(i);
    }
    f[v]=++tt;
}

int main(){

    memset(table,0,sizeof(table));
    memset(vis,0,sizeof(vis));
    int u,k,num;
    cin>>n;
    for(int i=1;i<=n;i++){
        cin>>u>>k;
        while(k--){
            cin>>num;
            table[u][num]=1;
        }
    }

    for(int i=1;i<=n;i++){
        if(vis[i]==0)
            dfs(i);
    }

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

}

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

struct node {
    int start = 0;
    int end = 0;
};

void depth_search(map<int, vector<int> > &a, map<int, node> &nodes, int &time, int current) {
    time++;
    nodes[current].start = time;
    for (int i=0; i<a[current].size(); i++) {
        if ( nodes[a[current][i]].start == 0 ) {
            depth_search(a, nodes, time, a[current][i]);
        }
    }
    time++;
    nodes[current].end = time;
}

int main() {
    int n;
    cin >> n;
    map<int, vector<int> > a;
    for (int i=0; i<n; i++) {
        int u, k, v;
        cin >> u >> k;
        for (int j=0; j<k; j++) {
            cin >> v;
            a[u].push_back(v);
        }
    }
    
    int time = 0;
    map<int, node> nodes;
    for (int i=0; i<n; i++) {
        node nd; 
        nodes[i] = nd;
    }
    for (int i=1; i<=n; i++) {
        if ( nodes[i].start == 0 ) {
            depth_search(a, nodes, time, i);
        }
    }
    
    for (int i=1; i<=n; i++) {
        cout << i << " " << nodes[i].start << " " << nodes[i].end << endl;
    }
}

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

using namespace std;

const int max_v = 100;
vector<vector<int> > adj_list;
int d[max_v] = { 0 };
int f[max_v] = { 0 };
int discovered[max_v] = { 0 };
int t = 1;

// Depth-first Search ( Stack implementation)
void DFS(int v)
{
	stack<int> S;
	S.push(v);
	discovered[v] = 1;
	d[v] = t++;
	int i = 0;
	while (!S.empty()) {
		v = S.top();
		if (i < adj_list[v - 1].size()) {
			int u = adj_list[v - 1][i++];
			if (discovered[u] == 0) {
				discovered[u] = 1;
				d[u] = t++;
				S.push(u);
				i = 0;
			}
		}
		else {
			S.pop();
			f[v] = t++;
			i = 0;
		}
	}
}

int main(int argc, char** argv)
{
	// Input
	int n;
	int u, k;
	cin >> n;
	for (int i = 0; i < n; i++) {
		cin >> u >> k;
		int v;
		vector<int> adj;
		for (int j = 0; j < k; j++) {
			cin >> v;
			adj.push_back(v);
		}
		adj_list.push_back(adj);
	}

	// Depth-first Search
	DFS(1);

	// Output
	for (int i = 1; i <=n; i++) {
		cout << i << " " << d[i] << " " << f[i] << endl;
	}

	return 0;
}