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++: #include <conio.h>
#include <cstdio>
#include <stack>
using namespace std;

#define start first
#define end second

static const int NOT   = false;
static const int WHITE = 1;
static const int GRAY  = 2;
static const int BLACK = 3;
static const int N	   = 101;

int  n;
int  VisitedInfo[N];
bool Graph[N][N];
pair< int, int > Time[N];

void dfs( int u );
int  nextNode( int u );

int main()
{

	int u, k, v;

	for( int i = 0; i < N; i++ ) {
		for( int j = 0; j < N; j++ ) Graph[i][j] = NOT;
		VisitedInfo[i] = WHITE;
	}

	scanf( "%d", &n );
	for( int i = 0; i < n; i++ ) {
		
		scanf( "%d %d", &u, &k );
		for( int j = 0; j < k; j++ ) {

			scanf( "%d", &v );
			Graph[u][v] = true;

		}

	}

	dfs( 1 );

	for( int i = 1; i <= n; i++ ) printf( "%d %d %d\n", i, Time[i].start, Time[i].end );

	return 0;

}

void dfs( int u )
{

	int  time = 1, pos, ppos;
	bool brkUpNodeFlg = false;
	stack< int > dfsInfo;

	dfsInfo.push( u );
	Time[u].start  = time;
	VisitedInfo[u] = GRAY;

	while( !dfsInfo.empty() ) {

		ppos = dfsInfo.top();

		if( !brkUpNodeFlg ) pos = nextNode( ppos );

		brkUpNodeFlg = false;

		if( pos != 0 ) {
			if( VisitedInfo[pos] == WHITE ) {

				dfsInfo.push( pos );
				Time[pos].start  = ++time;
				VisitedInfo[pos] = GRAY;

			}
		}
		if( pos == 0 && VisitedInfo[ppos] != WHITE ){

			dfsInfo.pop();
			Time[ppos].end	  = ++time;
			VisitedInfo[ppos] = BLACK;


		}

		if( dfsInfo.empty() ) {
			for( int i = 1; i <= n; i++ ) {
				if( VisitedInfo[i] == WHITE ) {

					pos = i;
					dfsInfo.push( pos );
					Time[pos].start  = ++time;
					VisitedInfo[pos] = GRAY;
					brkUpNodeFlg     = true;
					break;

				}
			}
		}

	}

}

int nextNode( int now )
{

	for( int i = 1; i <= n; i++ ) {
		if( Graph[now][i] && VisitedInfo[i] == WHITE ) return i;
	}

	return 0;

}

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

using namespace std;

int n;
int G[105][105];
vector<int> d(105,0),f(105,0);
int t=1;

void dfs(int x){
    if(d[x]==0) d[x]=t;
    for (int j=1; j<=n; j++) {
        if (G[x-1][j-1]==1 and d[j]==0) {
            t++;//5
            dfs(j);
        }
    }
    t++;
    if(f[x]==0) f[x]=t;
}


int main(){
    cin >> n;
    for (int i =0; i<n; i++) {
        for (int j =0; j<n; j++) {
            G[i][j] = 0;
        }
    }
    for (int i=0;i<n;i++) {
        int p,m;
        cin >>p >> m;
        for (int j=0; j<m; j++) {
            int q;
            cin >> q;
            G[p-1][q-1]=1;
        }
    }
    dfs(1);
    for (int i=1; i<=n; i++) {
        cout << i << " "<<d[i]<<" "<<f[i]<<endl;
    }
}

C++: #include <iostream>
#include <vector>
#define WHITE 0
#define GRAY 1
#define BLACK 2
using namespace std;

int N, k, tt=0, starttime[100], stoptime[100], color[100]={0};
vector<int> E[100];

void dfsfunc(int node){
    //cout << node << " OKdfsfunc" << endl;
    tt++;
    starttime[node] = tt;
    color[node] = GRAY;
    for(int i=0;i<E[node].size();i++){
        if(color[E[node][i]]==WHITE){
            dfsfunc(E[node][i]);
        }
    }
    tt++;
    stoptime[node] = tt;
    color[node] = BLACK;
}

void dfs(){
    for(int node=0;node<N;node++){
        if(color[node]==WHITE) dfsfunc(node);
    }
    //cout << "OK" << endl;
}

int main(){
    cin >> N;
    for(int i=0;i<N;i++) {
        cin >> k;
        cin >> k;
        //cout << "OK" << endl;
        for(int j=0;j<k;j++) {
            int node;
            cin >> node;
            node--;
            E[i].push_back(node);
        }
    }
    //cout << "OK" << endl;
    dfs();
    for(int i=0;i<N;i++) cout << i+1 << " " << starttime[i] << " " << stoptime[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;

//??¶????????°
int n;
//?????\??????
int M[N][N];
//??°?????¶???????¢????
int color[N];
//??\??¶????????°??¶???
int d[N];
//??\??¶???????????¶???
int f[N];
//??¶???
int tt;
//???????????????????????????????????????
//?????¨?????????????????¨????????\??????????????????
int nt[N];

//????????????????????????u?????????v
int next(int u){
    for(int v=nt[u];v<n;v++){
        nt[u]=v+1;
        if(M[u][v]&&color[v]==WHITE)
            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){
            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++)
        nt[i]=0,color[i]=WHITE;
    tt=0;

    //??\????????????u?????????????????±?????????????´¢
    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();
}

C++: #include "bits/stdc++.h"

using namespace std;

void dfs(int curr, int& ts, const vector<set<int> >& graph
        , vector<int>& d, vector<int>& f) {

    ++ts;
    d[curr] = ts;
    const set<int>& nextNodes = graph[curr];
    for (int n : nextNodes) {
        if (d[n] > 0) {
            continue;
        }
        dfs(n, ts, graph, d, f);
    }
    ++ts;
    f[curr] = ts;
}

void Main() {
    int n;
    cin >> n;
    vector<set<int> > graph(n, set<int>());
    for (int i = 0; i < n; ++i) {
        int u, k;
        cin >> u >> k;
        --u;
        for (int j = 0; j < k; ++j) {
            int v;
            cin >> v;
            --v;
            graph[u].insert(v);
        }
    }

    vector<int> d(n, -1);
    vector<int> f(n, -1);
    int timestamp = 0;
    for (int i = 0; i < n; ++i) {
        if (d[i] < 0) {
            dfs(i, timestamp, graph, d, f);
        }
    }
    for (int i = 0; i < n; ++i) {
        cout << (i + 1) << " " << d[i] << " " << f[i] << endl;
    }
}

int main() {
    std::cout << std::fixed << std::setprecision(15);
    Main();
    return 0;
}