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 <stack>
using namespace std;

int main()
{
    int n;
    cin >> n;
    int Adj[n][n] = {};
    int time[n][2] = {};
    for (int i = 0; i < n; i++)
    {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; j++)
        {
            int v;
            cin >> v;
            Adj[u - 1][v - 1] = 1;
        }
    }

    stack<int> s;
    int current_time = 1;
    for (int i = 0; i < n; i++)
    {
        if (time[i][0] == 0)
        {
            int src = i;
            s.push(src);
            while (!s.empty())
            {
                int cur = s.top();
                s.pop();
                //cout << cur << " " << current_time << endl;
                if (time[cur][0] == 0)
                {
                    time[cur][0] = current_time;
                    s.push(cur);
                    for (int dst = n - 1; dst >= 0; dst--)
                    {
                        //cout << cur << " " << dst << " " << Adj[cur][dst] << endl;
                        if (Adj[cur][dst] && time[dst][0] == 0)
                        {
                            s.push(dst);
                        }
                    }
                    current_time++;
                }
                else if (time[cur][0] != 0 && time[cur][1] == 0)
                {
                    time[cur][1] = current_time;
                    current_time++;
                }
            }
        }
    }

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

    return 0;
}

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<vector<bool>> explored;
    vector<int> tmp;
    // vector<bool> flag;
    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);
            // flag.push_back(false);
        }
        // if(num==0){
        //     flag.push_back(false);
        // }
        vertex.push_back(tmp);
        // explored.push_back(flag);
        tmp.clear();
        // flag.clear();
    }
    int cnt = 1;
    bool check;
    int s;
    st.push(0);
    do{
        s = st.top();

        if((vnum[s][0]==0) && d[s]==0){
            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){
            vflag[s] = true;
            d[s] = cnt++;
            f[s] = cnt++;
            st.pop();
        }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 <cstdio>

static const int MAX=100;
static const int WHITE=0;
static const int GRAY=1;
static const int BLACK=2;
static const int NIL=-1;

using namespace std;

int adj[MAX+1][MAX+1];
int color[MAX+1],d[MAX+1],f[MAX+1];
stack<int> S;
int n;
int t=0;

int next(int u){
  for(int i=1;i<=n;i++){
    if(adj[u][i]==1&&color[i]==WHITE) return i;
  }
  return NIL;
}

void dfs(int u){
  S.push(u);
  color[u]=GRAY;
  d[u]=++t;
  while(S.empty()==false){
    u=S.top();
    int v=next(u);
    if(v!=NIL){
      color[v]=GRAY;
      d[v]=++t;
      S.push(v);
    }else{
      S.pop();
      color[u]=BLACK;
      f[u]=++t;
    }
  }
}

void dfs_init(){
  for(int i=1;i<=n;i++) color[i]=WHITE;
  for(int i=1;i<=n;i++){
    if(color[i]==WHITE) dfs(i);
  }
}

int main(){
  cin >> n;
  for(int i=1;i<=n;i++){
    int u,k; cin >> u >> k;
    for(int i=1;i<=n;i++) adj[u][i]=0;
    for(int i=0;i<k;i++){
      int v; cin >> v;
      adj[u][v]=1;
    }
  }
  dfs_init();
  for(int id=1;id<=n;id++){
    printf("%d %d %d\n",id,d[id],f[id]);
  }
}