Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

func max(a, b int) int {
	if a > b {
		return a
	} else {
		return b
	}
}

func min(a, b int) int {
	if a > b {
		return b
	} else {
		return a
	}
}

//solve

const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 最初にiを訪問した時刻。発見時刻
//f[i]: iの隣接リストを訪問し終えた時刻。完了時刻
var color, d, f [MAX]int

func dfs_visit(u int) {
	color[u] = GRAY
	time++
	d[u] = time
	//隣接を調べる
	for v := 0; v < n; v++ {
		if M[u][v] == 0 {
			continue
		}
		//隣接するvが、未訪問だった場合
		if color[v] == WHITE {
			dfs_visit(v)
		}
	}
	//訪問完了処理
	color[u] = BLACK
	time++
	f[u] = time
	//訪問完了
}

func dfs() {
	//初期化
	for u := 0; u < n; u++ {
		color[u] = WHITE
	}
	time = 0

	//未訪問のuを始点として、深さ優先探索
	for u := 0; u < n; u++ {

		if color[u] == WHITE {
			dfs_visit(u)
		}
	}

	for u := 0; u < n; u++ {
		fmt.Println(u+1, d[u], f[u])
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	dfs()

}

C++: #include <bits/stdc++.h>
using namespace std;
#define WHITE 0
#define GRAY 1
#define BLACK 2

int M[101][101];
int d[101], f[101];
int searchPos[101];
int color[101];
int tt = 0;
int n;
stack<int> s;

int nextPoint(int curPoint){
    for(int i=searchPos[curPoint];i<n;++i){
        searchPos[curPoint] += 1;
        if(M[curPoint][i]==1 && color[i] == WHITE){
            return i;
        }
    }
    return -1;
}

void dfs(int point){
    d[point] = ++tt;
    color[point] = GRAY;
    while(1){
        int next = nextPoint(point);
        if(next != -1){
            dfs(next);
        }
        else{
            f[point] = ++tt;
            color[point] = BLACK;
            return;
        }
    }
}

int main(){
    int u, z, y;
    scanf("%d",&n);
    for(int i=0;i<n;++i){
        searchPos[i] = 0;
        color[i] = WHITE;
        for(int j=0;j<n;++j){
            M[i][j] = 0;
        }
    }
    for(int i=0;i<n;++i){
        cin >> u >> z;
        for(int j=0;j<z;++j){
            cin >> y;
            M[u-1][y-1] = 1;
        }
    }

    dfs(0);
    for(int i=0;i<n;++i){
        if(color[i]==WHITE){
            dfs(i);
        }
    }
    for(int i=0;i<n;++i){
        printf("%d %d %d\n",i+1,d[i],f[i]);
    }
    return 0;
}

C++: #include<cstdio>
#define MAX_N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n, u, k, v;
int adj[MAX_N][MAX_N];
int color[MAX_N], d[MAX_N], f[MAX_N], tt;

void dfs_visit(int num){
	color[num] = GRAY;
	d[num] = ++tt;
	for(int i = 0; i < n; i++){
		if(adj[num][i] == 0) continue;
		if(color[i] == WHITE){
			dfs_visit(i);
		}
	}
	color[num] = BLACK;
	f[num] = ++tt;
}

void dfs(){
	for(int i = 0; i < n; i++){
		color[i] = WHITE;
	}
	tt = 0;

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

int main(void){
	scanf("%d", &n);

	for(int i = 0; i < n; i++){
		for(int j = 0; j < n; j++){
			adj[i][j] = 0;
		}
	}

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

	dfs();

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

	return 0;
}

C++: #include <cstdio>
#include <iostream>

using namespace std;

//4
//1 1 2
//2 1 4
//3 0
//4 1 3

//1 1 8
//2 2 7
//3 4 5
//4 3 6

const int MAX = 100;

int n;

int t = 0;

int G[MAX + 1][MAX + 1];
int d[MAX + 1];
int f[MAX + 1];

int color[MAX + 1];
int WHITE = 0;
int GRAY = 1;
int BLACK = 2;

void dfs(int v) {
	color[v] = GRAY;
	d[v] = ++t;

	for (int i = 1; i <= n; ++i) {
		if (G[v][i] == 1 && color[i] == WHITE)
			dfs(i);
	}

	color[v] = BLACK;
	f[v] = ++t;
}

int main() {

	scanf("%d", &n);

	for (int i = 0; i <= n; ++i) {
		for (int j = 0; j <= n; ++j)
			G[i][j] = 0;
	}

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

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

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

	return 0;

}

C++: #include <iostream>
#include <iomanip>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <algorithm>
#include <cstdio>
#include <utility>
#include <string>
#include <cmath>
#include <cstdlib>
#include <cstring>

using namespace std;

typedef uint64_t u64;
typedef int64_t s64;
typedef uint32_t u32;
typedef int32_t s32;
typedef vector<s32> vs32;
typedef vector<u32> vu32;
typedef vector<s64> vs64;
typedef vector<u64> vu64;

const double PI=3.14159265358979323846;

#define MAX(x, y) ((x) < (y) ? (y) : (x))
#define MIN(x, y) ((x) > (y) ? (y) : (x))

#define rep(i, N) for(int i = 0; i < N; ++i)

#define CEIL(x, y) (((x) + (y) - 1) / (y))
#define MOD 1000000007ULL

class DirectedGraph
{
public:
    DirectedGraph()
    : t(1)
    {}
    DirectedGraph(int n)
    : t(1), g(vector< vs32 >(n)), d(vs32(n, 0)), f(vs32(n, 0))
    {}
    ~DirectedGraph() {}

    void dfs(int i)
    {
        d[i] = t++;
        rep (j, g[i].size())
        {
            if (d[g[i][j]] == 0)
            {
                dfs(g[i][j]);
            }
        }
        f[i] = t++;
    }

    int t;
    vector< vs32 > g;
    vs32 d;
    vs32 f;
};

int main()
{
    cin.tie(0);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;

    DirectedGraph dg(n);
    int u, v;
    int c;
    rep (i, n)
    {
        cin >> u >> c;
        --u;
        dg.g[u].resize(c);
        rep (j, c)
        {
            cin >> v;
            --v;
            dg.g[u][j] = v;
        }
    }

    rep (i, n)
    {
        if (dg.d[i] == 0)
        {
            dg.dfs(i);
        }
    }

    rep (i, n)
    {
        cout << i + 1 << " " << dg.d[i] << " " << dg.f[i] << "\n";
    }
    return 0;
}

C++: 
#include<iostream>

using namespace std;

const int MAX = 100;

void search(bool graph[MAX][MAX], int find[], int done[], int n, int u,int& count) {
	count++;
	find[u] = count;
	for (int i = 0; i < n; i++) {
		if (graph[u][i] && find[i] == 0) {
			search(graph, find, done, n, i, count);
		}
	}
	count++;
	done[u] = count;
}

int main() {
	bool check[MAX] = { false };
	int find[MAX] = { 0 };
	int done[MAX] = { 0 };
	bool graph[MAX][MAX] = { {false} };
	int N;

	cin >> N;
	for (int i = 0; i < N; i++) {
		int u, k;
		cin >> u >> k;
		for (int j = 0; j < k; j++) {
			int temp;
			cin >> temp;
			graph[u - 1][temp - 1] = true;
		}
	}

	int count = 0;
	for (int i = 0; i < N; i++) {
		if (find[i] == 0) {
			search(graph, find, done, N, i, count);
		}
	}

	for (int i = 0; i < N; i++) {
		cout << i + 1 << " " << find[i] << " " << done[i] << endl;
	}

	return 0;
}