Go: package main

import (
	"bufio"
	"bytes"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

const N = 100

const (
	WHITE = iota
	GRAY
	BLACK
)

type Graph struct {
	M               [N][N]int
	color, d, f, nt [N]int
	tt              int
}

func (g *Graph) next(u, n int) int {
	for v := g.nt[u]; v < n; v++ {
		g.nt[u] = v + 1
		if g.M[u][v] != 0 {
			return v
		}
	}
	return -1
}

func (g *Graph) dfsVisit(r, n int) {
	var S []int
	S = append([]int{r}, S...)
	g.color[r] = GRAY
	g.tt++
	g.d[r] = g.tt

	for len(S) != 0 {
		u := S[0]
		v := g.next(u, n)
		if v == -1 {
			S = S[1:]
			g.color[u] = BLACK
			g.tt++
			g.f[u] = g.tt
			continue
		}

		if g.color[v] != WHITE {
			continue
		}

		g.color[v] = GRAY
		g.tt++
		g.d[v] = g.tt
		S = append([]int{v}, S...)
	}
}

func (g *Graph) dfs(n int) string {
	for i := 0; i < n; i++ {
		g.color[i] = WHITE
	}
	g.tt = 0

	for u := 0; u < n; u++ {
		if g.color[u] == WHITE {
			g.dfsVisit(u, n)
		}
	}

	var out bytes.Buffer
	for i := 0; i < n; i++ {
		out.WriteString(fmt.Sprintf("%d %d %d\n", i+1, g.d[i], g.f[i]))
	}

	return strings.TrimRight(out.String(), "\n")
}

func answer(reader io.Reader) string {
	sc := bufio.NewScanner(reader)
	sc.Split(bufio.ScanWords)

	sc.Scan()
	n, _ := strconv.Atoi(sc.Text())

	var g Graph
	for i := 0; i < n; i++ {
		sc.Scan()
		u, _ := strconv.Atoi(sc.Text())
		sc.Scan()
		k, _ := strconv.Atoi(sc.Text())
		u--
		for j := 0; j < k; j++ {
			sc.Scan()
			v, _ := strconv.Atoi(sc.Text())
			v--
			g.M[u][v] = 1
		}
	}

	return g.dfs(n)
}

func main() {
	fmt.Println(answer(os.Stdin))
}

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

struct time_check {
    int find_time, end_time;
};

int G[101][101] = {0};
time_check t[101];
int elapsed = 0, n;
stack<int> S;

void dfs(int start) {
    S.push(start);
    while (! S.empty()) {
        elapsed++;
        int u = S.top();
        for (int i = 1; i <= n + 1; i++) {
            if (G[u][i] == 1 && t[i].find_time == 0) {
                t[i].find_time = elapsed;
                G[u][i] = 0;
                S.push(i);
                break;
            }
            if (i == n + 1) {
                t[u].end_time = elapsed;
                S.pop();
            }
        }
    }
}

int main() {
    for (int i = 1; i <= 100; i++) t[i].end_time = 0;

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

    for (int i = 1; i <= n; i++) {
        if (t[i].end_time == 0) {
            t[i].find_time = ++elapsed;
            dfs(i);
        }
    }

    for (int i = 1; i <= n; i++) {
        cout << i << " " << t[i].find_time << " " << t[i].end_time << endl;
    }

    return 0;
}

/*
#include<iostream>
#include<stack>
using namespace std;
static const int N = 100;
static const int WHITE = 0;
static const int GRAY = 1;
static const int BRACK = 2;

int n, M[N][N];
int color[N], d[N], f[N], tt;
int nt[N];

// uに隣接するvを番号順に取得
int next(int u) {
    for (int v = nt[u]; v < n; v++) {
        nt[u] = v + 1;
        if (M[u][v]) return v;
    }
    return -1;
}

// スタックを用いた深さ優先探索
void dfs_visit(int r) {
    for (int i = 0; i < n; i++) nt[i] = 0;

    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] = BRACK;
            f[u] = ++tt;
        }
    }
}

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

    // 未訪問のuを始点として深さ優先探索
    for (int u = 0; u < n; u++) {
        if (color[u] == WHITE) dfs_visit(u);
    }
    for (int i = 0; i < n; i++) {
        cout << i+1 << " " << d[i] << " " << f[i] << endl;
    }
}

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

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

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

    dfs();

    return 0;
}
*/

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

const int LEN = 100;
const int UNVISITED = 0;
const int FOUND = 1;
const int DONE = 2;

// 再帰関数による深さ優先探索
void dfs_visit(int n, int u, vector<vector<int> >& M, vector<int>& status, vector<int>& d, vector<int>& f, int& tt){
    // 頂点uの訪問状態を「発見」にし,その時刻を記録
    status[u] = FOUND;
    d[u] = ++tt; // ttをインクリメントしてからd[u]に代入

    int v;
    for(v = 0; v < n; v++){
        if(M[u][v] == 0) continue; // 0:隣接していない
        if(status[v] == UNVISITED){
            dfs_visit(n, v, M, status, d, f, tt);
        }
    }

    // 頂点uの訪問状態を「完了」にし,その時刻を記録
    status[u] = DONE;
    f[u] = ++tt; // ttをインクリメントしてからf[u]に代入
}

void dfs(int n, vector<vector<int> >& M){
    vector<int> status(LEN); // status:頂点の訪問状態
    vector<int> d(LEN); // d:頂点の発見時刻
    vector<int> f(LEN); // d:頂点の完了時刻
    int tt; // tt:時刻

    // 初期化 (頂点uの訪問状態を「未訪問」に,また時刻を0に)
    int u;
    for(u = 0; u < n; u++){
        status[u] = UNVISITED;
    }
    tt = 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(status[u] == UNVISITED){
            dfs_visit(n, u, M, status, d, f, tt);
        }
    }

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

int main(){
    int n; // n:頂点数
    vector<vector<int> > M(LEN, vector<int> (LEN)); //  M:頂点同士の隣接を表す行列
    int u, v, k, i, j; // 入力受け取り用

    // 頂点数を受け取り,隣接行列を初期化
    cin >> n;
    int m;
    for(m = 0; m < n; m++){
        for (j = 0; j < n; j++){
            M[m][j] = 0;
        }
    }

    // 頂点番号,出次数,隣接する頂点番号を受け取り,隣接行列に反映
    for(i = 0; i < n; i++){
        cin >> u >> k;
        u--;
        for(j = 0; j < k; j++){
            cin >> v;
            v--;
            M[u][v] = 1;
        }
    }

    dfs(n, M);

    return 0;
}

C++: #include<bits/stdc++.h>
using namespace std;
vector<int> v[105];
int n,step=0,fdepth[105],sdepth[105];
bool visit[105];
void dfs(int node){
    step++;
    fdepth[node]=step;
    int l=v[node].size();
    for(int i=0;i<l;i++)
        if(!visit[v[node][i]]){
            visit[v[node][i]]=1;
            dfs(v[node][i]);
        }
    step++;
    sdepth[node]=step;
}
int allvisit(void){
    for(int i=1;i<=n;i++)
        if(!visit[i])
            return i;
    return 0;
}
int main(){
    ios_base::sync_with_stdio(0);
    //cin.tie(0);
    while(cin>>n){
        memset(fdepth,0,sizeof(fdepth));
        memset(sdepth,0,sizeof(sdepth));
        memset(visit,0,sizeof(visit));
        for(int i=1;i<=n;i++)
            v[i].clear();
        int parent,num,son;
        for(int i=0;i<n;i++){
            cin>>parent>>num;
            while(num--){
                cin>>son;
                v[parent].push_back(son);
            }
        }
        step=0;
        visit[1]=1;
        dfs(1);
        while(allvisit()){
            step=0;
            int node=allvisit();
            visit[node]=1;
            dfs(node);
        }
        for(int i=1;i<=n;i++)
            cout<<i<<' '<<fdepth[i]<<' '<<sdepth[i]<<'\n';
    }
    return 0;
}