Go: package main

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

var sc = bufio.NewScanner(os.Stdin)
var depth [101]int
var finish [101]int
var d [101]int
var n, time int

func nextInt() int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return i
}
func visit(graph [][]int, u int) {
	depth[u] = 1
	time++
	d[u] = time
	for i := 0; i < n; i++ {
		if graph[u][i] == 1 {
			if depth[i] == 0 {
				visit(graph, i)
			}
		}
	}
	depth[u] = 2
	time++
	finish[u] = time
}
func main() {
	sc.Split(bufio.ScanWords)

	n = nextInt()
	graph := make([][]int, n)
	for i := 0; i < n; i++ {
		graph[i] = make([]int, n)
	}
	for i := 0; i < n; i++ {
		s := nextInt()
		t := nextInt()
		if t == 0 {
			continue
		}
		for i := 0; i < t; i++ {
			u := nextInt()
			graph[s-1][u-1] = 1
		}
	}
	for i := 0; i < n; i++ {
		if depth[i] == 0 {
			visit(graph, i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, d[i], finish[i])
	}
}

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;
}

C++: #include <sstream>
#include <string>
#include <vector>
#include <map>
#include <algorithm>
#include <iostream>
#include <utility>
#include <set>
#include <cctype>
#include <queue>
#include <stack>
#include <cstdio>
#include <cstdlib>
#include <cmath>
using namespace std;

#define MAXN 100
int n, timecount = 1;
int ans[MAXN][MAXN];
int d[MAXN], f[MAXN]; // d[i]はdを最初に発見した時刻,f[i]は調べ終わった時刻

int dfs(int p);

int main(void) {
    cin >> n;
    for (int i = 0; i < n; i++) {
        d[i] = -1;
        f[i] = -1;
    }
    for (int i = 0; i < n; i++)
        for (int j = 0; j < n; j++)
            ans[i][j] = 0;
    for (int i = 0; i < n; i++) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++) {
            int tmp;
            cin >> tmp;
            ans[u-1][tmp-1] = 1;
        }
    }
//    for (int i = 0; i < n; i++) {
//        for (int j = 0; j < n; j++) {
//            if (j == n-1) cout << ans[i][j];
//            else cout << ans[i][j] << " ";
//        }
//        cout << endl;
//    }
    dfs(0);
    for (int i = 0; i < n; i++) {
        printf("%d %d %d\n", i+1, d[i], f[i]);
    }
    return 0;
}

int dfs(int p)
{
    int ret = 0, count = 1;
    if (d[p] == -1) d[p] = timecount++;
    for (int i = 0; i < n; i++) {
        if (ans[p][i] == 1 && f[i] == -1) {
            dfs(i);
        }
    }
    if (f[p] == -1) f[p] = timecount;
    timecount++;
    return 0;
}

C++: #include <utility>
#include <math.h>
#include <vector>
#include <algorithm>
#include <string>
#include <iostream>

using namespace std;

int c;
int a[100][100];
int times = 0;
vector<pair<int,int> > v;

vector<int> search(int node)
{
    vector<int> r;
    for(int i = 0;i<c;i++)
    {
        if(a[node][i] == 1)
            r.push_back(i);
    }
    return r;
}

int deep(int node)
{
    if(v[node].first == 0)
    {
        v[node].first = ++times;
        vector<int> r = search(node);
        for(int i = 0;i<r.size();i++)
        {
            deep(r[i]);
            
        }
        v[node].second = ++times;
    }
    else
        return -1;

    return 1;
}

int main() {

    cin >> c;
    for(int i= 0;i<c;i++)
        for(int j = 0;j<c;j++)
            a[i][j] = 0;
    v = vector<pair<int,int> >(c,{0,0});
    for(int i = 0; i<c;i++)
    {
        int rem[2];
        cin >> rem[0] >> rem[1];
        for(int j = 0;j<rem[1];j++)
        {
            int rem11;
            cin >> rem11;
            a[i][rem11-1] = 1;
        }
    }//cin fin
    deep(0);
    
    for(int i = 0; i<c;i++)
    {
        cout << i+1 << " " << v[i].first << " " << v[i].second << endl;
    }
    
    return 0;
}

C++: #include<bits/stdc++.h>
#define fi first
#define se second
#define rep(i, n) for(int (i) = 0; (i) < (n); (i)++)
#define rrep(i, n) for (int (i) = 1; (i) <= (n); (i++))
#define rng(a) a.begin(),a.end()
#define rrng(a) a.rbegin(),a.rend()
#define pb push_back
#define eb emplace_back
#define yn {puts("Yes");}else {puts("No");}
#define printd(x) printf("%.12f\n", ans);
template<class T> bool chmin(T& a, const T& b) {if (a > b) {a = b; return 1;} return 0;}
template<class T> bool chmax(T& a, const T& b) {if (a < b) {a = b; return 1;} return 0;}
using namespace std;
using ll = long long;
using P = pair<int, int>;

vector<vector<int>> g(105);
vector<bool> visited(105);
vector<int> d(105, -1);
vector<int> f(105);

int nowTime = 0;

int dfs(int s) {
	visited[s] = true;
	nowTime++;
	if (d[s] == -1) d[s] = nowTime;

	for(auto v: g[s]) {
		if (visited[v]) continue;
		dfs(v);
	}
	
	bool ok = true;
	for (auto v: g[s]) {
		if (visited[v]) continue;
		ok = false;
	}
	if (ok) f[s] = nowTime + 1;
	return nowTime++;
}


int main(void) {
	int n;
	cin >> n;
	rep (i, n) {
		int u, k;
		cin >> u >> k;
		u--;
		rep (j, k) {
			int v;
			cin >> v;
			v--;
			g[u].pb(v);
		}
	}

	rep (i, n) if (!visited[i]) dfs(i);

	rep (i, n) cout << i + 1 << " " << d[i] << " " << f[i] << endl;
	return 0;
}