Go: package main

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

// repr state of visited node
// WHITE yet visit
// GEAY  visiting
// BLACK visited
const (
	WHITE int = iota
	GRAY
	BLACK
)

type dfsGraph struct {
	g      [][]int
	colors []int
	stime  []int // Start time of visiting node
	ftime  []int // Finish time of visiting node
}

var time int

func makeAdjList() [][]int {
	var n int
	fmt.Scanf("%d", &n)

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

	sc := bufio.NewScanner(os.Stdin)
	for i := 0; i < n; i++ {
		sc.Scan()
		nodeInfo := strings.Split(sc.Text(), " ")
		outDegree, _ := strconv.Atoi(nodeInfo[1])

		if outDegree > 0 {
			for k := 0; k < outDegree; k++ {
				j, _ := strconv.Atoi(nodeInfo[k+2])
				j-- // convert 1 based to 0 based
				adj[i][j] = 1
			}
		}
	}

	return adj
}

func (dg dfsGraph) dfsVisit(u int) {
	// 頂点uを訪問中に設定
	dg.colors[u] = GRAY
	time++
	dg.stime[u] = time

	// uの隣接nodeを訪問
	for v := 0; v < len(dg.g); v++ {
		if dg.g[u][v] == 0 {
			continue // 辺がなければスキップ
		}

		// vが未訪問なら訪問
		if dg.colors[v] == WHITE {
			dg.dfsVisit(v)
		}
	}

	// 頂点uを訪問済みに設定
	dg.colors[u] = BLACK
	time++
	dg.ftime[u] = time
}

func (dg dfsGraph) dfs() {
	for i := 0; i < len(dg.g); i++ {
		if dg.colors[i] == WHITE {
			dg.dfsVisit(i)
		}
	}
}

func (dg dfsGraph) printDfsTime() {
	for i := 0; i < len(dg.g); i++ {
		fmt.Printf("%d %d %d\n", i+1, dg.stime[i], dg.ftime[i])
	}
}

func main() {
	adj := makeAdjList()
	colors := make([]int, len(adj))
	stime := make([]int, len(adj))
	ftime := make([]int, len(adj))
	graph := dfsGraph{adj, colors, stime, ftime}
	graph.dfs()
	graph.printDfsTime()
}

C++: #include <bits/stdc++.h>
using namespace std;
#define FOR(i,o,n) for(long long i = o;i<n;i++)
#define oneforall ios::sync_with_stdio(false);cin.tie(0);
#define all(v) (v).begin(),(v).end()
#define ini(...) int __VA_ARGS__; in(__VA_ARGS__)
#define inl(...) long long __VA_ARGS__; in(__VA_ARGS__)
#define ins(...) string __VA_ARGS__; in(__VA_ARGS__)
#define int long long 
const long long inf=1e18;
void in(){} template <typename T,class... U> void in(T &t,U &...u){ cin >> t; in(u...);}
void out(){cout << "\n";} template <typename T,class... U> void out(const T &t,const U &...u){ cout << t; if(sizeof...(u)) cout << " "; out(u...);}
typedef vector<int> vi;
typedef vector<long long> vl;
typedef long long ll;
typedef vector<pair<long, long > > vpll;
typedef vector<pair<int, int > > vpii;
#define FORR(x,arr) for(auto& x:arr)
#define ZERO(a) memset(a,0,sizeof(a))





//3111111111111111111111111111111

	int n;
	vi childs[310];
	bool visit[310];
	int deep[310][2];
	int dep = 0;
	void dfs(int x){

		visit[x] = 1;
		deep[x][0] = dep;
		FORR(x1,childs[x])if(!visit[x1]){
			dep++;
			dfs(x1);
		}
		dep++;
		deep[x][1] = dep;
	}




	void solve(){
		
		in(n);
		FOR(i,0,n){
			ini(x);
			ini(x1);
			FOR(i1,0,x1){
				ini(tmp1);
				childs[x].push_back(tmp1);
			}
		}
		int tmp = 0;
		while(tmp!=n){
			FOR(i,1,n+1){if(visit[i])tmp++;else{
				tmp = 0;
				dep++;
				dfs(i);
				i = 0;
			}}
		}
		FOR(i,1,n+1){
			out(i,deep[i][0],deep[i][1]);
		}








		
		
	}























int32_t main() {
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall
	oneforall 
	oneforall

	solve();
	


	return 0;
}

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

int n, t, G[101][101], S[101], T[101];

void dfs(int p) {
    if (S[p] != 0) return;
    S[p] = ++t;
    for (int i = 0; i < n; i++)
        if (G[p][i] == 1)
            dfs(i);

    T[p] = ++t;
}


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

    t = 0;
    for (int i = 0; i < n; i++)
        dfs(i);

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

    return 0;
}

C++: #include<iostream>

using namespace std;

int A[101][100];//データを入れる配列
int d[101];
int f[101];
int t = 1;//time

int Depth(int n){
    if((f[n] != 0)){//既に探索が終了していたら、その節点は飛ばす
        return 0;
    }
    if(d[n] == 0){//はじめて通る節点だったら、dに時間を記録
        d[n] = t;
        t++;
    }
    if((A[n][0] != 0)){//隣接点が1つ以上ある場合は以下のループに入る
        for(int i=1; i<=A[n][0]; i++){
            //if(A[n][i] == n){//自分自身に返ってくるノードだったら、
            //    f[A[n][i]] = t;
            //    t++;
            //    return 0;
            //}
            if((A[n][i] != n) && (d[A[n][i]] == 0)){
                Depth(A[n][i]);
            }
        }
    }
    f[n] = t;
    t++;
}

int main(){
    int n, num;
    cin >> n;
    for(int k=1; k<=n; k++){
        d[k] = 0;
        f[k] = 0;
    }
    for(int i=1; i<=n; i++){
        cin >> num;
        cin >> A[i][0];
        for(int j=1; j<=A[i][0]; j++){
            cin >> A[i][j];
        }
    }

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

C++: #include <bits/stdc++.h>
using namespace std;
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

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

int next(int u){//ntってなに？？現在地？
	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) {
	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] = BLACK;
			f[u] = ++tt;
		}
	}
}

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

	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;
}