Go: package main

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

var N int
var A [][]int
var t int
var color, d, f []int

const (
	WHITE = iota
	GRAY
	BLACK
)

func dfsVisit(u int) {
	color[u] = GRAY
	t ++
	d[u] = t
	for v:=0; v<N; v++ {
		if A[u][v] == 0 {
			continue
		}
		if color[v] == WHITE {
			dfsVisit(v)
		}
	}
	color[u] = BLACK
	t++
	f[u] = t
}

func dfs() {
	for u:=0; u<N; u++ {
		if color[u] == WHITE {
			dfsVisit(u)
		}
	}
	for u:=0; u<N; u++{
		fmt.Printf("%d %d %d\n", u+1, d[u], f[u])
	}
}


func nextInt(scanner *bufio.Scanner) int {
	scanner.Scan()
	num, _ := strconv.Atoi(scanner.Text())
	return num
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	N = nextInt(scanner)
	color = make([]int, N)
	d = make([]int, N)
	f = make([]int, N)
	A = make([][]int, N)
	for i:=0; i<N; i++{
		A[i] = make([]int, N)
	}
	for i:=0; i<N; i++{
		index := nextInt(scanner) - 1
		cnt := nextInt(scanner)
		for j:=0; j<cnt; j++ {
			v := nextInt(scanner) - 1
			A[index][v] = 1
		}
	}
	dfs()
}

C++: #include<iostream>
#include<vector>
#include<queue>
#include"print_vec.h"

using namespace std;

vector<vector<int>> adjacent;
vector<pair<int, int>> ans;
vector<bool>checked;

//?????????is????????????
int dfs(int now,int time = 1) {
	cout << now << endl;
	ans[now].first = time;
	checked[now] = true;
	for (int i = 0; i < adjacent[now].size(); i++) {
		if (!checked[adjacent[now][i]]) {
			time = dfs(adjacent[now][i], time + 1);
		}
	}
	ans[now].second = time+1;
	return time + 1;
}

int main() {
	int n;
	cin >> n;
	adjacent = vector<vector<int>>(n);
	checked = vector<bool>(n, false);
	ans.resize(n);

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

	dfs(0, 1);
	
	for (int i = 0; i < n; i++) {
		cout << i + 1 << " " << ans[i].first << " " << ans[i].second << endl;
	}

}

C++: #include <iostream>
#include <string>
#include <cstring>
#include <fstream>
#include <cmath>
#include <iomanip>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <map>
#include <deque>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <list>
#include <unordered_map>
#include <bitset>
#include <sstream>
#define mop 1000000007

using namespace std;

static const int WHITE = 0;
static const int GRAY = 1;
static const int BLACK = 2;

int m[101][101] = {};
int nt[101] = {};
int n;
int color[101] = {};
int d[101] = {};
int f[101] = {};
int tt = 0;

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

void dfs_visit(int r){
    stack<int> S;
    S.push(r);
    color[r] = GRAY;
    d[r] = ++tt;

    while(!S.empty()){
        int u = S.top();
        int v = next(u);
        if(v != -1){
            if (color[v] == WHITE){
                color[v] = GRAY;
                d[v] = ++tt;
                S.push(v);
            }
        }else{
            S.pop();
            color[u] = BLACK;
            f[u] = ++tt;
        }
    }
}

void dfs(){

    for (int u=1;u<=n;u++){
        if(color[u] == WHITE){
            dfs_visit(u);
        }
    }
    for (int i=1;i<=n;i++){
        cout << i << " " << d[i] << " " << f[i] << endl;
    }
}

int main() {
    
    cin >> n;
    for (int u=1;u<=n;u++){
        nt[u] = 1;
    }
    for (int i=1;i<=n;i++){
        int x,k;
        cin >> x >> k;
        for (int j=1;j<=k;j++){
            int p;
            cin >> p;
            m[i][p] = 1;
        }
    }
    dfs();

}

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

const int MAX = 105;
int n;
int am[MAX][MAX];
int d[MAX], f[MAX], t, color[MAX], nt[MAX];

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

void dfs_visit(int r) {
  stack<int> S;
  S.push(r);
  color[r] = 1;
  d[r] = ++t;

  while (!S.empty()) {
    int u = S.top();
    int v = next(u);
    if (v != -1) {
      if (color[v] == 0) {
      color[v] = 1;
      d[v] = ++t;
      S.push(v);
      }
    } else {
    S.pop();
    color[u] = 2;
    f[u] = ++t;
    }
  }
}

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

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

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

C++: #include <algorithm>
#include <iostream>
#include <string>
#include <cstring>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <deque>
#include <iomanip>
#include <limits>
#include <map>
#include <queue>
#include <stack>
#include <vector>

#define FOR(i,k,n) for(int (i) = (k); (i) < (n); ++(i))
#define rep(i,n) FOR(i,0,n)
#define pb push_back
#define all(v) begin(v), end(v)
#define debug(x) cerr << #x << ": " << x << endl
#define debug2(x,y) cerr << #x << ": " << x << ", " << #y << ": " << y << endl

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<i_i, int> p_i;
typedef vector<int> vi;
typedef vector<vector<int>> vvi;
template<class T> using vv=vector<vector<T>>;
typedef deque<int> di;
typedef deque<deque<int>> ddi;

short d[101] = {}, v[101] = {};
bool  p[101][101] = {};
short t = 0;
int n;  

void dfs(int i) {
    if(d[i] != 0) return;
    d[i] = ++t;
    rep(j,n+1) {
        if(p[i][j] == 1 & d[j] == 0) {
            dfs(j);     
        }
    }
    v[i] = ++t;
}

int main() {
    cin >> n;
    rep(i,n) {
        short u,k;
        cin >> u >>k; 
        rep(j,k) {
            int tmp;
            cin >> tmp;
            p[u][tmp] = 1; 
        }
    }
    FOR(i,1,n+1) {
        dfs(i);
    }
    FOR(i,1,n+1) {
        cout << i << " " << d[i] << " " << v[i] << endl;
    }
	return 0;
}

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

int n;
int x[101][101];
int color[101], a[101], b[101];
int t;

void  DFS_VISIT(int u) {
	color[u] = 1;
	a[u] = ++t;
	for (int v = 0;v < n;v++) {
		if (x[u][v] == 0) {
			continue;
		}
		if (color[v] == 0) {
			DFS_VISIT(v);
		}
	}
		color[u] = 2;
		b[u] = ++t;

}

void DFS() {
	for (int u = 0;u < n;u++) {
		color[u] = 0;
	}
	t = 0;
	for (int u = 0;u < n;u++) {
		if (color[u] == 0) {
			DFS_VISIT(u);
		}
	}
	for (int u = 0;u < n;u++) {
		cout << u + 1<<" " << a[u]<<" " << b[u] << endl;;
	}
}

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

	DFS();

	return 0;
}

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

int n, t;
int v[100][100];
int d[100], f[100];

void stamp(int id) {
	if (t > 2 * n)
		return;

	if (d[id - 1] == 0) {
		d[id - 1] = t;
		t++;
		int i = 0;
		while (v[id - 1][i] == 0)
			i++;
		if (i < n && d[i] == 0)
			stamp(i + 1);
		else
			stamp(id);
	}
	else if (f[id - 1] == 0) {
		f[id - 1] = t;
		t++;

		int i = id - 1;
		while (d[i] != 0)
			i++;
		if (i < n)
			stamp(i + 1);
		else {
			int i = n - 1;
			while (v[i][id - 1] == 0)
				i--;
			stamp(i + 1);
		}
	}
	else
		return;
}

int main()
{
	cin >> n;

	for (int i = 0; i < n; i++) {
		d[i] = 0;
		f[i] = 0;
	}

	for (int i = 0; i < n; i++)
		for (int j = 0; j < n; j++)
			v[i][j] = 0;

	for (int i = 0; i < n; i++) {
		int u, k, s;

		cin >> u >> k;

		for (int j = 0; j < k; j++) {
			cin >> s;
			v[u - 1][s - 1] = 1;
		}
	}

	t = 1;
	stamp(1);

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

	return 0;
}