Go: package main

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

type TimeRecord struct {
	discoverTime int
	finishTime   int
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	timeRecordMap := make([]TimeRecord, n)
	childrenMap := make([][]int, n)
	for i := 1; i <= n; i++ {
		node, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		timeRecordMap[node-1] = TimeRecord{-1, -1}

		childNum, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		childrenMap[node-1] = make([]int, childNum)
		for j := 0; j < childNum; j++ {
			child, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			childrenMap[node-1][j] = child
		}
	}

	// TODO: always start with 1?
	timer := 1
	visit(1, &timer, childrenMap, timeRecordMap)
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func visit(currentNode int, timer *int, childrenMap [][]int, timeRecordMap []TimeRecord) {
	if timeRecordMap[currentNode-1].discoverTime > 0 {
		return
	}
	children := childrenMap[currentNode-1]
	timeRecordMap[currentNode-1] = TimeRecord{*timer, timeRecordMap[currentNode-1].finishTime}
	(*timer)++
	for i := 0; i < len(children); i++ {
		visit(children[i], timer, childrenMap, timeRecordMap)
	}
	timeRecordMap[currentNode-1] = TimeRecord{timeRecordMap[currentNode-1].discoverTime, *timer}
	(*timer)++
}

func nextInt(sc *bufio.Scanner) (int, error) {
	sc.Scan()
	return strconv.Atoi(sc.Text())
}

C++: // 深さ優先探索
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<stack>
#include<algorithm>
#include<iostream>
#include<cmath>
#include<vector>

using namespace std;

#define MAX_N 100
// 値の定義
const int EXIST = 1;
const int NO_EXIST = 0;

const int WHITE = 0;// 未訪問
const int GRAY = 1; // 訪問中
const int BLACK = 2;// 訪問完了

// グラフ情報を保持する配列
int ary_graph[MAX_N + 1][MAX_N + 1];

// 各頂点の訪問状態を保持する配列
int color[MAX_N + 1];

// 発見時刻と完了時刻を保持する構造体
typedef struct
{
    int start_time;
    int end_time;
}SearchTime;

SearchTime st_SearchTime[MAX_N];
int search_T = 0;

void depthFirstSearch(int now_vertex, int vertex_num);

int main(void)
{
    int n, u, num, v_num;

    for(int i = 0; i < MAX_N + 1; i++)
    {
        color[i] = WHITE;

        for(int j = 0; j < MAX_N + 1; j++)
        {
            // 配列の初期化
            ary_graph[i][j] = NO_EXIST;
        }
    }

    cin >> n;

    for(int i = 0; i < n; i++)
    {
        cin >> u;
        cin >> num;

        for(int j = 0; j < num; j++)
        {
            // 隣接点を記憶する
            cin >> v_num;
            ary_graph[u][v_num] = EXIST;
        }
    }

    // 深さ優先探索を実施
    for(int i = 1; i <= n; i++)
    {
        if( color[i] == WHITE )
        {
            depthFirstSearch(i, n);
        }
    }

    // 結果の表示
    for(int i = 1; i <= n; i++)
    {
        printf("%d %d %d\n", i, st_SearchTime[i].start_time, st_SearchTime[i].end_time);
    }

    return 0;
}

// 深さ優先探索を実施する関数
// now_vertex : 現在の頂点のNo.
// next_vertex : 次の頂点のNo.
// vertex_num : グラフの頂点数
void depthFirstSearch(int now_vertex, int vertex_num)
{
    // 訪問中
    color[now_vertex] = GRAY;

    // 発見時刻の設定
    search_T++;
    st_SearchTime[now_vertex].start_time = search_T;

    for(int i = 1; i <= vertex_num; i++)
    {
        if( color[i] == WHITE
            && ary_graph[now_vertex][i] == EXIST )
        {
            depthFirstSearch(i, vertex_num);
        }
    }

    // 訪問完了
    color[now_vertex] = BLACK;

    // 終了時刻の設定
    search_T++;
    st_SearchTime[now_vertex].end_time = search_T;

    return;
}

C++: #define _USE_MATH_DEFINES
#include "bits/stdc++.h"
using namespace std;

//#define int long long
#define DBG 0
#define dump(o) if(DBG){cerr<<#o<<" "<<o<<endl;}
#define dumpc(o) if(DBG){cerr<<#o; for(auto &e:(o))cerr<<" "<<e;cerr<<endl;}
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define rrep(i,a,b) for(int i=(b)-1;i>=(a);i--)
#define each(it,c) for(auto it=(c).begin();it!=(c).end();it++)
#define all(c) c.begin(),c.end()
const int INF = sizeof(int) == sizeof(long long) ? 0x3f3f3f3f3f3f3f3fLL : 0x3f3f3f3f;
const int MOD = (int)(1e9 + 7);

signed main() {
	int n; cin >> n; vector<vector<int> >vec(n, vector<int>());
	rep(i, 0, n) {
		int u, k; cin >> u >> k;
		u--;
		rep(j, 0, k) {
			int v; cin >> v; v--;
			vec[u].push_back(v);
		}
	}
	const int DONE = 1;
	const int YET = 0;
	vector<int>check(n, 0);
	vector<pair<int, int> >stamp(n);
	stack<int>S;
	S.push(0);
	int t = 1;

	while (!S.empty()) {
		int u = S.top();
		if (check[u] == YET) {
			stamp[u].first = t++;
			check[u] = DONE;
		}
	here:
		if (DBG) {
			cout << "t == " << t << endl;
			rep(x, 0, n) {
				cout << x+1<<" "<<stamp[x].first << " " << stamp[x].second << endl;
			}
		}
		rep(i, 0, vec[u].size()) {
			if (check[vec[u][i]] == YET) {
				S.push(vec[u][i]);
				check[vec[u][i]] = DONE;
				stamp[vec[u][i]].first = t++;
				u = vec[u][i];
				goto here;
			}
		}
		u = S.top(); S.pop();
		stamp[u].second = t++;
	}
	
	rep(i, 0, n) {
		cout << i + 1 << " " << stamp[i].first << " " << stamp[i].second << endl;;
	}

	return 0;
}

C++: #include <cstdio>
int dt[101][101];
int d[101], f[101];

int n;
int t=1;
void dfs(int s){
	d[s]=t++;
	for(int i=1;i<=n;i++){
		if(dt[s][i]&&d[i]==0){
			dfs(i);
		}
	}
	f[s]=t++;
}
int main(){
	int fi, v, g;
	scanf("%d",&n);
	for(int i=1;i<=n;i++){
		scanf("%d %d",&fi,&v);
		for(int j=1;j<=v;j++){
			scanf("%d",&g);
			dt[fi][g]=1;
		}
	}
	d[1]=1;
	int flag=true;
	dfs(1);
	for(int i=1;i<=n;i++){
		if(!d[i]){
			dfs(i);
		}
	}
			
	for(int i=1;i<=n;i++){
		printf("%d %d %d\n",i,d[i],f[i]);
	}
	return 0;
}

C++: #include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<math.h>
#include<stack>

int main(){
    int n;
    scanf("%d",&n);
    int a[n+1][n+1];
    int i,j;
    for(i=1;i<=n;i++)for(j=1;j<=n;j++)a[i][j]=0;
    for(i=1;i<=n;i++){
        int q,k;
        scanf("%d %d",&q,&k);
        for(j=1;j<=k;j++) {
            int p;
            scanf("%d",&p);
            a[q][p]=1;
        }
    }
    int time=0;
    std::stack<int>S;
    int ans[n+1][3];
    
    
    
    S.push(1);
    time++;
    ans[1][1]=time;
    
    int color[n+1];
    color[1]=1;
    for(i=2;i<=n;i++)color[i]=0;//0??????????¨????
    
    while(S.size()>=1){
        int flag=0;//flag=0??????pop
        for(i=1;i<=n;i++){
            if(i!=S.top()&& a[S.top()][i]==1 &&color[i]==0){
                S.push(i);
                color[i]=1;
                time++;
                ans[i][1]=time;
                flag=1;
                break;
            }
        }
        if(flag==0){
            time++;
            ans[S.top()][2]=time;
            S.pop();
        }
    }
    
    for(i=1;i<=n;i++){
        printf("%d %d %d\n",i,ans[i][1],ans[i][2]);
        
    }
    
    
    return 0;
}