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
	startNode := 1
	for {
		visit(startNode, &timer, childrenMap, timeRecordMap)
		startNode = findStartNode(childrenMap, timeRecordMap)
		if startNode < 0 {
			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
		}
	}
	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 <iostream>
#include <vector>

using namespace std;

int tim = 0;
vector<vector<int>> to;
vector<bool> reached;
vector<int> d;
vector<int> f;



void dfs(int point);

int main()
{
    int n;
    cin >> n;
    to.resize(n+1);
    for(int i = 1; i <= n; i++){
        int m;
        cin >> m;
        cin >> m;
        to[i].resize(m);
        for(int j = 0; j < m; j++){
            cin >> to[i][j];
        }
    }
    
    reached.resize(n+1);
    d.resize(n+1);
    f.resize(n+1);

    dfs(1);

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

    return 0;
}

void dfs(int point)
{
    tim++;
    reached[point] = true;
    d[point] = tim;
    for(int i = 0; i < to[point].size(); i++){
        if(!reached[to[point][i]]){
            dfs(to[point][i]);
        }
    }
    tim++;
    f[point] = tim;
}

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

int n, dd[100], f[100], tmap[100][100];
int color[100], t = 1;
stack<int> S;

int a(){
	int d = S.top();
	dd[d] = t;
	t++;
	color[d] = 1;
	cout << d << "??????" <<endl;
	for (int i = 1; i <= n; i++){
		if (color[i] == 0 && tmap[d][i] == 1){
			cout << d << "  " << i << "  " << t << endl;
			S.push(i);
			a();
		}
	}
	cout << d << "??????" << endl;
	f[d] = t;
	t++;
	return 0;
}


int main(){
	cin >> n;
	for (int i = 0; i < 100; i++){
		dd[i] = f[i] = color[i] = 0;
		for (int j = 0; j < 100; j++){
			tmap[i][j] = 0;
		}
	}

	int u, k, v;

	for (int i = 0; i < n; i++){
		cin >> u >> k;
		for (int j = 0; j < k; j++){
			cin >> v;
			tmap[u][v] = 1;
		}
	}
	S.push(1);
	a();
	for (int i = 1; i <= n; i++){
		cout << i << " " << dd[i] << " " << f[i] << endl;
	}
	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;

int n;
vector < int > G[105];
int st[105] = {};
int et[105];
int t = 1;

void dfs(int v)
{
    if ( st[v] != 0 ) return;
    st[v] = t;
    t++;
    for ( auto &x : G[v] ) {
        dfs(x);
    }
    et[v] = t;
    t++;
}

int main()
{
    cin >> n;
    for ( int i = 0; i < n; i++ ) {
        int u, k;
        cin >> u >> k;
        for ( int j = 0; j < k; j++ ) {
            int v;
            cin >> v;
            G[u].push_back(v);
        }
        sort(begin(G[u]), end(G[u]));
    }

    for ( int i = 1; i <= n; i++ ) dfs(i);
    
    for ( int i = 1; i <= n; i++ ) {
        cout << i << " " << st[i] << " " << et[i] << endl;
    }

    return (0);
}

C++: #include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef pair<ll,ll> pl;
typedef vector<pl> vp;
#define fore(i,a,b) for(ll i=(a);i<=(b);++i)
#define rep(i,n) fore(i,0,(n)-1)
#define rfore(i,a,b) for(ll i=(b);i>=(a);--i)
#define rrep(i,n) rfore(i,0,(n)-1)
#define all(x) (x).begin(),(x).end()
const ll INF=1001001001;
const ll LINF=1001001001001001001;
const ll D4[]={0,1,0,-1,0};
const ll D8[]={0,1,1,0,-1,-1,1,-1,0};
template<class T>
bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}return 0;}
template<class T>
bool chmin(T &a,const T &b){if(b<a){a=b;return 1;}return 0;}
template<class T>
ll sum(const T& a){return accumulate(all(a),0LL);}

ll n;
ll now;
vector<vector<bool> > g;
vector<bool> used;
vl startTime,endTime;
void dfs(ll idx){
    used[idx]=1;
    startTime[idx]=++now;
    rep(i,n){
        if(g[idx][i]&&!used[i])dfs(i);
    }
    endTime[idx]=++now;
}
void solve(){
    cin>>n;
    g=vector<vector<bool> >(n,vector<bool>(n));
    used=vector<bool>(n);
    startTime=vl(n);
    endTime=vl(n);
    rep(i,n){
        ll idx,m;cin>>idx>>m;
        idx--;
        rep(k,m){
            ll to;cin>>to;to--;
            g[idx][to]=true;
        }
    }
    rep(i,n){
        if(!used[i])dfs(i);
    }
    rep(i,n){
        cout<<(i+1)<<" "<<startTime[i]<<" "<<endTime[i]<<endl;
    }
}

int main(){
    cin.tie(0);
    ios::sync_with_stdio(0);
    solve();
}

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

using namespace std;

#define MAX 110
int num;
int matrix[MAX][MAX];
int dst[MAX];

void input(){
    for(int i=0;i<MAX;i++){
        dst[i] = -1;
        for(int j=0;j<MAX;j++){
            matrix[i][j] = 0;
        }
    }
    for(int i=1;i<=num;i++){
        int v; cin >> v;
        int tmp; cin >>tmp;
        for(int j=0;j<tmp;j++){
            int vi; cin >> vi;
            matrix[v-1][vi-1] = 1;
        }
    }
}

void bfs(){
    stack<int> S;
    S.push(0);
    dst[0] = 0;
    while(S.size() != 0){
        int cur = S.top();
        for(int i=0;i<num;i++){
            if(matrix[cur][i]==1){
                if(dst[i]==-1){
                    S.push(i);
                    dst[i] = dst[cur] + 1;
                }
            }
        }
        S.pop();
    }
    for(int i=0;i<num;i++){
        cout << i+1 << " " <<  dst[i] << endl;
    }
}

int main(){
    cin >> num;
    input();
    bfs();
}

C++: #include <bits/stdc++.h>
#define rep(i, n) for(int i = 0; i < (n); i++)
using namespace std;
using ll = long long;
using pii = pair<int, int>;

vector<vector<int>> g;
vector<int> d, f;

void dfs(int v, int &t) {
	d[v] = t++;
	for (auto nv : g[v]) {
		if (d[nv]) continue;
		dfs(nv, t);
	}
	f[v] = t++;
}

int main() {
	int n;
	cin >> n;
	g.resize(n);
	rep(i, n) {
		int u, k;
		cin >> u >> k;
		u--;
		rep(i, k) {
			int v;
			cin >> v;
			v--;
			g[u].push_back(v);
		}
	}
	d.assign(n, 0);
	f.assign(n, 0);
	int t = 1;
	for (int i = 0; i < n; i++) {
		if (d[i]) continue;
		dfs(i, t);
	}
	rep(i, n) {
		cout << i + 1 << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}