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 <iostream>
#include <iomanip> // << fixed << setprecision(xxx)
#include <algorithm> // do { } while ( next_permutation(A, A+xxx) ) ;
#include <vector>
#include <string> // to_string(nnn) // substr(m, n) // stoi(nnn)
#include <complex>
#include <tuple> // get<n>(xxx)
#include <queue>
#include <stack>
#include <map> // if (M.find(key) != M.end()) { }
#include <set> // S.insert(M);
// if (S.find(key) != S.end()) { }
// for (auto it=S.begin(); it != S.end(); it++) { }
// auto it = S.lower_bound(M);
#include <random> // random_device rd; mt19937 mt(rd());
#include <cctype>
#include <cassert>
#include <cmath>
#include <cstdio>
#include <cstdlib> // atoi(xxx)
using namespace std;

#define DEBUG 0 // change 0 -> 1 if we need debug.
// insert #if<tab> by my emacs. #if DEBUG == 1 ... #end

typedef long long ll;

// const int dx[4] = {1, 0, -1, 0};
// const int dy[4] = {0, 1, 0, -1};

// const int C = 1e6+10;
// const ll M = 1000000007;

class Edge {
public:
  int src, dst, cost;
  Edge(int s, int d, int c)
    : src(s), dst(d), cost(c) {}
  friend bool operator<(const Edge& x, const Edge& y) {
    return x.cost < y.cost;
  }
};

typedef Edge State;

class Graph {
public:
  int N;
  vector<Edge>* V;
  int* visited;
  int* from;
  int time;
  int* time_d;
  int* time_f;

  Graph(int n)
    : N(n), time(0) {
    V = new vector<Edge>[N];
    from = new int[N];
    time_d = new int[N];
    time_f = new int[N];
    visited = new int[N];
    fill(visited, visited+N, 0);
  }
  ~Graph() {
    delete[] V;
    delete[] from;
    delete[] time_d;
    delete[] time_f;
    delete[] visited;
  }

  void add_edge(int src, int dst, int cost = 1) {
    V[src].push_back(Edge(src, dst, cost));
  }

  void dfs(int start) {
    stack<State> S;
    S.push(State(-1, start, 0));
    while (!S.empty()) {
      State s = S.top();
      S.pop();
      if (visited[s.dst] == 0) {
        visited[s.dst] = 1;
        time_d[s.dst] = time++;
        from[s.dst] = s.src;
        S.push(s);
        for (auto x : V[s.dst]) {
          if (visited[x.dst] == 0) {
            S.push(State(s.dst, x.dst, s.cost + x.cost));
          }
        }
      } else if (visited[s.dst] == 1) {
        visited[s.dst] = 2;
        time_f[s.dst] = time++;
      }
    }
  }
};

int main () {
  int n;
  cin >> n;
  Graph graph(n);
  for (auto i = 0; i < graph.N; ++i) {
    int u, k;
    cin >> u >> k;
    --u;
    for (auto j = 0; j < k; ++j) {
      int v;
      cin >> v;
      --v;
      graph.add_edge(u, v);
    }
  }
  for (auto i = 0; i < graph.N; ++i) {
    sort(graph.V[i].begin(), graph.V[i].end());
    reverse(graph.V[i].begin(), graph.V[i].end());
  }
  while (true) {
    bool used = false;
    for (auto i = 0; i < graph.N; ++i) {
      if (graph.visited[i] == 0) {
        graph.dfs(i);
        used = true;
        break;
      }
    }
    if (!used) break;
  }
  for (auto i = 0; i < graph.N; ++i) {
    cout << i+1
         << " " << graph.time_d[i]+1
         << " " << graph.time_f[i]+1 << endl;
  }
}

C++: #include <iostream>
#include <vector>
using namespace std;

int t = 0;
vector<int> edge[101];
bool back_edge[101];

pair<int, int> visit_time[101];

void dfs(int cur)
{
    t += 1;
    visit_time[cur].first = t;

    for (int i = 0; i < (int)edge[cur].size(); i++) // cur から行ける頂点について
    {
        if (back_edge[edge[cur][i]] == false)
        {
            back_edge[edge[cur][i]] = true;
            dfs(edge[cur][i]);
        }
    }

    t += 1;
    visit_time[cur].second = t;
}

int main()
{
    int n;
    cin >> n;

    for (int i = 0; i < n; i++)
    {
        int u, k;
        cin >> u >> k;
        back_edge[u] = false;
        for (int j = 0; j < k; j++)
        {
            int v;
            cin >> v;
            edge[u].push_back(v);
        }
    }

    for (int i = 1; i < n; i++)
        if (back_edge[i] == false)
        {
            back_edge[i] = true;
            dfs(i);
        }

    for (int i = 1; i <= n; i++)
    {
        cout << i
             << " " << visit_time[i].first
             << " " << visit_time[i].second << endl;
    }
}

C++: #include<stdio.h>
#include<iostream>
#define N 100
#define WHITE 0
#define GRAY 1
#define BLACK 2

int n,M[N][N];
int color[N],d[N],f[N],tt;

void dfs_visit(int u){
    int v;
    color[u]=GRAY;
    d[u]=++tt; //最初の訪問
    for(v=0; v<n; v++){
        if(M[u][v]==0){ continue; }
        if(color[v]==WHITE){ dfs_visit(v); } 
    }
    color[u]=BLACK;
    f[u]=++tt;//訪問の完了
}

void dfs(){
    int u;
    //初期化
    for(u=0; u<n; u++){ 
        color[u]=WHITE; 
    }

    tt=0;

    for(u=0; u<n; u++){
        //未訪問のuを始点として深さ優先探索
        if(color[u]==WHITE){ dfs_visit(u); }
    }

    for(u=0; u<n; u++){
        printf("%d %d %d\n",u+1,d[u],f[u]);
    }
}

int main(){
    int u,v,k,i,j;

    scanf("%d",&n);
    for(i=0; i<n; i++){
        for(j=0; j<n; j++){
            M[i][j]=0;
        }
    }

    for(i=0; i<n; i++){
        scanf("%d %d",&u,&k);
        u--;
        for(j=0; j<k; j++){
            scanf("%d",&v);
            v--;
            M[u][v]=1;
        }
    }

    dfs();

    return 0;
}