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>
#include <stack>

using namespace std;

int main(){
    stack<int> st;
    int n;
    cin >> n;
    int d[n] = {};
    int f[n] = {};
    int vnum[n][2] = {};
    bool vflag[n] = {};
    int tmp2;
    int num;
    vector<vector<int>> vertex;
    vector<int> tmp;
    for(int i=0;i<n;i++){
        cin >> num;
        cin >> num;
        vnum[i][0] = num;
        for(int j=0;j<num;j++){
            cin >> tmp2;
            tmp.push_back(tmp2);
        }
        vertex.push_back(tmp);
        tmp.clear();
    }
    int cnt = 1;
    bool check;
    int s;
    st.push(0);
    do{
        s = st.top();

        if(((vnum[s][0]==0) && d[s]==0) || (s==vertex[s][vnum[s][1]]-1)){
            vflag[s] = true;
            d[s] = cnt++;
            f[s] = cnt++;
            st.pop();
        }else if(vnum[s][0]==vnum[s][1]){
            vflag[s] = true;
            f[s] = cnt++;
            st.pop();
        }else if((vflag[vertex[s][vnum[s][1]]-1]) && (f[vertex[s][vnum[s][1]]-1]!=0) && (d[s]==0)){
            if(vnum[s][0]-vnum[s][1]==1){
                vflag[s] = true;
                d[s] = cnt++;
                f[s] = cnt++;
                st.pop();
            }else{
                vnum[s][1]++;
            }
        }else if(vflag[vertex[s][vnum[s][1]]-1]){
            vflag[s] = true;
            f[s] = cnt++;
            st.pop();
        }else if(vflag[s]){
            st.push(vertex[s][vnum[s][1]++] - 1);
        }else{
            if(d[s]==0){
                d[s] = cnt++;
            }
            st.push(vertex[s][vnum[s][1]++] - 1);
        }
        check = !st.empty();
        if(!check){
            for(int i=0;i<n;i++){
                if(vflag[i]==false){
                    check = true;
                    st.push(i);
                    break;
                }
            }
        }
    }while(check);

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

C++: #include<iostream>
#include<stack>
#include<string.h>
using namespace std;
//void haichi(int);
int MA[101][101];
int n,cnt=1,Flag;
int id[101],d[101],f[101];
stack<int> S;
int main(void){
	int u,k,v;
	memset(MA,0,sizeof(MA));
	for(int i=1;i<=100;i++){
		id[i] = 0;
		d[i] = 0;
		f[i] = 0;
	}
	cin >> n;
	for(int i=0;i<n;i++){
		cin >> u >> k;
		for(int j=0;j<k;j++){
			cin >> v;
			MA[u][v]=1;
		}
	}
	S.push(1);
	d[1] = 1;
	while(!S.empty()){
		Flag=0;
		/*if(d[S.top()] == 0)
			d[S.top()]=cnt;*/
		cnt++;
		for(int i=1;i<=n;i++){  //i=S.top();
			if(MA[S.top()][i]==1 && d[i] == 0){
				MA[S.top()][i]=0;
				S.push(i);
				//cout << "PUSH " << S.top() << endl;;
				d[S.top()]=cnt;
				Flag=1;
				break;
			}
		}
		if(Flag==0){
			//cout << "POP " << S.top() << endl;
			if(f[S.top()]==0) f[S.top()] = cnt;
			S.pop();
		}
	}
	for(int i=1;i<=n;i++){
		cout << i << " " << d[i] << " " << f[i] << endl;
	}
	return 0;
}

C++: //16D8103013E Sen Shunkou
#include<iostream>
int main(){
    int n;
    std::cin>>n;
    int A[n][n];
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            A[i][j]=0;
        }
    }
    int tmp,s,e;
    for(int i=0;i<n;i++){
        std::cin>>s;
        std::cin>>tmp;
        for(int j=0;j<tmp;j++){
            std::cin>>e;
            A[s-1][e-1]=1;
        }
    }

    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            if(j==0){
                std::cout<<A[i][j];
            }else std::cout<<" "<<A[i][j];
        }
        std::cout<<"\n";
    }
    return 0;
}

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

#define ll long long
#define vvi vector<vector<int>>
#define vec vector
#define pq priority_queue
#define all(v) (v).begin(), (v).end()
#define uniqueV(x) sort(x.begin(), x.end()); x.erase(unique(x.begin(), x.end()), x.end());
#define rep(i, n) for (int (i) = (0); (i) < (n); ++(i))
#define repp(i, m, n) for (int (i) = (m); (i) < (n); ++(i))
#define debug(x) cerr << #x << ": " << x << endl;
#define debug2(x, y) cerr<<"("<<#x<<", "<<#y<<") = "<<"("<<x<<", "<<y<<")"<<endl;
#define debug3(x, y, z) cerr<<"("<<#x<<", "<<#y<<", "<<#z<<") = "<<"("<<x<<", "<<y<<", "<<z<<")"<<endl;
#define debugB(x, y) cerr<<#x<<": "<<bitset<y>(x) << endl;
#define line() cerr << "---------------" << endl;

const int dx[] = {1, -1, 0, 0};
const int dy[] = {0, 0, -1, 1};

template<typename T>
void printA(vector<T> &printArray, char between = ' ') {
   int paSize = printArray.size();
   for (int i = 0; i < paSize; i++) { cerr << printArray[i] << between;}
   if (between != '\n') {cerr << endl;}
}

// ------------------------------------------------------------------------------------------
int N, turn;
int d[111], f[111];
vector<vector<int>> G;

void dfs(int from) {
   d[from] = ++turn;
   for (int to : G[from]) {
      if (!d[to]) dfs(to);
   }
   f[from] = ++turn;
}

int main() {
   // 入力
   cin >> N;
   G = vector<vector<int>>(N);
   rep (i, N) {
      int u, k;
      cin >> u >> k;
      u--;
      rep (j, k) {
         int a;
         cin >> a;
         a--;
         G[u].push_back(a);
      }
   }

   rep (i, N) {
      if (!d[i]) dfs(i);
   }

   rep (i, N) {
      printf("%d %d %d\n", i+1, d[i], f[i]);
   }

   return 0;
}

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

int num = 1;
bool visited[1000];
vector<int> v[1000], seq[1000];
void dfs(int k){
    seq[k].pb(num++);
    if(visited[k]) return;
    visited[k] = 1;
    for (auto t : v[k]){
        if(visited[t]) continue;
        dfs(t);
    }
    seq[k].pb(num++); return;

}
int main(){
    int n; cin >> n;
    memset(visited, 0, sizeof(visited));
    for (int i = 0; i < n; i++){
        int x, y, z; cin >> x >> y;
        for (int j = 0; j < y; j++){
            cin >> z; v[x].pb(z);
        }
    }
    for(int i = 1; i <= n; i++)
        sort(v[i].begin(), v[i].end());
    dfs(1);
    for (int i = 1; i <= n; i++){
        cout << i << ' ';
        for (auto k : seq[i])
        cout << k << ' ';
        cout << '\n';
    }
}