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
		}
	}

	timer := 1
	for {
		startNode := findStartNode(childrenMap, timeRecordMap)
		if startNode > 0 {
			visit(startNode, &timer, childrenMap, timeRecordMap)
		} else {
			break
		}
	}
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

func findStartNode(childrenMap [][]int, timeRecordMap []TimeRecord) int {
	x := -1
	for node, timeRecord := range timeRecordMap {
		if timeRecord.discoverTime < 0 {
			x = node + 1
			break
		}
	}
	if x < 0 {
		return -1
	}

	found := false
	i := 0
	for i < len(childrenMap) {
		children := childrenMap[i]
		for j := 0; j < len(children); j++ {
			if children[j] == x {
				x = j + 1
				found = true
				break
			}
		}
		if found {
			i = 0
		} else {
			i++
		}
	}
	return x
}

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++: #include <bits/stdc++.h>
#define ll long long
using namespace std;

struct ver{
    ll d;
    ll f;
};

ll t=0;
vector<vector<ll>> mat;
vector<ver> vers;

void find(ll pos) {
    if(vers[pos].d == 0){
        t++;
        vers[pos].d = t;
        for(ll i:mat[pos]) {
            find(i);
        }
        if(vers[pos].f == 0) {
            t++;
            vers[pos].f = t;
        }
    }
}

int main() {
    ll n;
    cin >> n;
    for(ll i=0;i<n;i++) {
        ll u,k;
        cin>>u>>k;
        vector<ll> aaa;
        for(ll j=0;j<k;j++) {
            ll tmp;
            cin>>tmp;
            aaa.push_back(tmp-1);
        }
        mat.push_back(aaa);
    }
    for(ll i=0;i<n;i++) {
        vers.push_back(ver{0,0});
    }
    for(ll i=0;i<n;i++) {
        if(vers[i].d == 0)find(i);
    }
    for(ll i=0;i<n;i++) {
        cout << i+1<<" "<<vers[i].d<<" "<<vers[i].f<<endl;
    }
}

C++: #include <iostream>
#include <vector>
#include <stack>

using namespace std;
const int INF = 1001001001;

void step1(vector< vector<int> >& edges, vector<int>& d, vector<int>& f, vector<int>& color, int node, int& time)
{
    // stackを使用
    stack<int> S;
    S.push(node);
    d[node] = ++time;
    color[node] = 1;
    while(!S.empty())
    {
        node = S.top();
        if(color[node] != 2){
            bool flag = true;
            for(int e : edges[node])
            {
                if(color[e] == 0)
                {
                    S.push(e);
                    d[e] = ++time;
                    color[e] = 1;
                    flag = false;
                    break;
                }
            }
            if(flag) color[node] = 2;
        }
        else
        {
            f[node] = ++time;
            S.pop();
        }
    }
}

void step2(vector< vector<int> >& edges, vector<int>& d, vector<int>& f, vector<int>& color, int node, int& time)
{
    d[node] = ++time;
    color[node] = 1;
    for(int e : edges[node])
        {
            if(color[e] == 0) step2(edges, d, f, color, e, time);
        }
    
    f[node] = ++time;
}

void dfs(vector< vector<int> >& edges, vector<int>& d, vector<int>& f, vector<int>& color, int n)
{
    int time=0;
    for(int i=0;i<n;++i)
    {
        if(color[i] == 0) step2(edges, d, f, color, i, time);
    }
}

int main()
{
    int n, u, k, e;
    cin >> n;
    vector< vector<int> > edges(n);
    vector<int> d(n), f(n), color(n);
    for(int i=0;i<n;++i)
    {
        //d[i] = f[i] = INF;
    }
    for(int i=0;i<n;++i)
    {
        cin >> u >> k;
        --u;
        for(int j=0;j<k;++j)
        {
            cin >> e;
            --e;
            edges[u].push_back(e);
            //edges[e].push_back(u);
        }
    }

    dfs(edges, d, f, color, n);
    for(int i = 0;i < n; ++i)
    {
        cout << i+1 << " " << d[i] << " " << f[i] << endl;
    }
}

C++: #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 BLACK=2;





//用栈实现深度优先搜索


/**
 * color 标记访问状态的数组，
 * M[N][N] 邻接矩阵 如果存在定点i到顶点j的边，则M[i][j]=trul
 * Stack 栈，暂存访问过程中的顶点
**/
int n,M[N][N];
int color[N],d[N],f[N],tt;
int nt[N];


//按序号，获取和u相邻的v
int next(int u){
    for(int v=nt[u];v<n;v++){
        nt[u]=v+1;
        if(M[u][v]) return v;
    }
    return -1;
}

//用栈实现深度优先搜索
void dfs(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(){
    //初始化
    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(u);
    }
    for(int i=0;i<n;i++){
        cout<<i+1<<" "<<d[i]<<" "<<f[i]<<endl;
    }
    return;
}
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 i=0;i<k;i++){
            cin>>v;
            v--;
            M[u][v]=1;
        }
    }

    dfs();
    return 0;
}