Go: package main

/*
深さ優先探索
*/

import (
	"bufio"
	"fmt"
	"log"
	"os"
	"strconv"
	"strings"
)

func main() {
	scanner := makeScanner(8192)
	n := eGetInt(scanner)
	g := make([][]int, n+1)
	for i := 1; i < n+1; i++ {
		ints := eGetInts(scanner)
		num, vcount := ints[0], ints[1]
		g[i] = make([]int, vcount)
		for j := 0; j < vcount; j++ {
			g[num][j] = ints[j+2]
		}
	}
	hist := make([]struct{ d, f int }, n+1)
	t := 0
	var visit func(int)
	visit = func(num int) {
		if hist[num].d == 0 {
			stack := []int{}
			t++
			hist[num].d = t
			stack = append(stack, num)
			for len(stack) > 0 {
				// トップを訪問する
				top := stack[len(stack)-1]
				for i := 0; i < len(g[top]); i++ {
					if hist[g[top][i]].d == 0 {
						t++
						hist[g[top][i]].d = t
						stack = append(stack, g[top][i])
						goto endloop
					}
				}
				// 訪問場所がなくなったら
				// pop
				stack = stack[0 : len(stack)-1]
				t++
				hist[top].f = t
			endloop:
			}
		}
	}
	for i := 1; i < n+1; i++ {
		visit(i)
	}
	for i := 1; i < n+1; i++ {
		fmt.Println(i, hist[i].d, hist[i].f)
	}
}

////////////////////////////////////////////////////////////////////////////////
// ライブラリ
////////////////////////////////////////////////////////////////////////////////
func makeScanner(maxByte int) *bufio.Scanner {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Buffer(make([]uint8, 0, 8192), maxByte)
	return scanner
}
func makeWordScanner() *bufio.Scanner {
	scanner := makeScanner(8192)
	scanner.Split(bufio.ScanWords)
	return scanner
}
func eGetLine(r *bufio.Scanner) string {
	if r.Scan() {
		return r.Text()
	}
	err := r.Err()
	if err != nil {
		log.Fatal(err)
	}
	// EOF
	return ""
}
func eGetInt(r *bufio.Scanner) int {
	line := eGetLine(r)
	return eAtoi(line)
}
func eGetInt64(r *bufio.Scanner) int64 {
	line := eGetLine(r)
	return eAtoInt64(line)
}
func eGetFields(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Fields(line)
}
func eGetInts(r *bufio.Scanner) []int {
	fields := eGetFields(r)
	ints := make([]int, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoi(fields[i])
	}
	return ints
}
func eGetInt64s(r *bufio.Scanner) []int64 {
	fields := eGetFields(r)
	ints := make([]int64, len(fields))
	for i := 0; i < len(ints); i++ {
		ints[i] = eAtoInt64(fields[i])
	}
	return ints
}
func eGetChars(r *bufio.Scanner) []string {
	line := eGetLine(r)
	return strings.Split(line, "")
}
func eAtoi(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		log.Fatal(err)
	}
	return n
}
func eAtoInt64(s string) int64 {
	n, err := strconv.ParseInt(s, 10, 64)
	if err != nil {
		log.Fatal(err)
	}
	return n
}

C++: #include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
#include<queue>
using namespace std;

int find_t[101],end_t[101];
int lft[101],rht[101];
int flag[101];
int t=1;

void DFS(int);
void Print();

int main(int argc,char* argv[]){
  int n,id,cnt,x;
  
  memset(find_t,255,sizeof(find_t));
  memset(end_t,0,sizeof(end_t));
  memset(lft,255,sizeof(lft));
  memset(rht,255,sizeof(rht));
  memset(flag,0,sizeof(flag));

  cin>>n;
  for(int i=0;i<n;i++){
    cin>>id>>cnt;
    flag[id]=0;
    for(int l=0;l<cnt;l++){
      cin>>x;
      (l==0) ? lft[id]=x : rht[id]=x;
    }
  }
  
  for(int i=1;i<=n;i++){
    if(flag[i]==0)
      DFS(i);
  }
  Print();
  
  return 0;
}

  void DFS(int p){
    if(flag[p]==0){
      find_t[p]=t++;
      flag[p]=1;
    }
    else
      return;
    
    if(lft[p]!=-1)
      DFS(lft[p]);
    if(rht[p]!=-1)
      DFS(rht[p]);

    end_t[p]=t++;
  }

  void Print(){
    for(int i=1;i<=100;i++){
      if(find_t[i]!=-1)
	printf("%d %d %d\n",i,find_t[i],end_t[i]);
    }
  }

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <climits>

using namespace std;

const int WHITE=0, GRAY=1, BLACK=2;

struct DFS {
    int n;
    vector<vector<int>> g;
    vector<int> discover;
    vector<int> finish;
    vector<int> state;
    int time = 1;
    
    DFS(int n):n(n) {
        g.assign(n, vector<int>());
        discover.assign(n, -1);
        finish.assign(n, -1);
        state.assign(n, WHITE);
    }
    
    void addEdge(int u, int v) {
        g[u].push_back(v);
    }
    
    void solve() {
        for (int i = 0; i < n; i++) {
            if (state[i] == WHITE) {
                dfs(i);
            }
        }
    }
    
    void dfs(int u) {
        state[u] = GRAY;
        discover[u] = time++;
        for (int v : g[u]) {
            if (state[v] == WHITE) {
                dfs(v);
            } 
        }
        finish[u] = time++;
        state[u] = BLACK;
    }
    
    void print() {
        for (int i = 0; i < n; i++) {
            cout << i << ":";
            for (int v : g[i]) {
                cout << v << " ";
            }
            cout << endl;
        }
    }
};

int main() {
    ios::sync_with_stdio(false);
    int n;
    cin >> n;
    DFS dfs(n);
    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--;
           dfs.addEdge(u, v);
       }
    }
    
    //dfs.print();
    
    dfs.solve();
    
    for (int i = 0; i < n; i++) {
        cout << (i + 1) <<  " " << dfs.discover[i] << " " << dfs.finish[i] << endl; 
    }
    
    return 0;
}

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

int n;
int g[101][101];
char c[101];
int visit[101];
int finish[101];
int main() {
    cin >> n;
    for (int i = 1; i <= n; ++i) {
        int u, k;
        cin >> u >> k;
        for (int j = 0; j < k; ++j) {
            int v;
            cin >> v;
            g[u][v] = 1;
        }

    }

   stack<int> s;
    for (int l = 1; l <= n; ++l) {
        c[l] = 'w';

    }
    int time = 0;
    int start = 0;
    int v;
    while(true) {
        start++;
        if(start == n) break;
        if(c[start] == 'w') {
            time++;
            s.push(start);
            c[start] = 'g';
            visit[start] = time;
            while (s.size() != 0) {
                time++;
                v = s.top();
                int next = -1;
                for (int i = 1; i <= n ; ++i) {
                    if(i == v) {
                        continue;
                    }
                    if(g[v][i] && c[i] == 'w') {
                        next = i;
                        break;
                    }
                }
                if(next == -1) {
                    c[v] = 'b';
                    finish[v] = time;
                    s.pop();
                } else {
                    c[next] = 'g';
                    visit[next] = time;
                    s.push(next);
                }
            }
        }
    }

    for (int m = 1; m <= n; ++m) {
        cout << m << " " << visit[m ] << " " << finish[m] << endl;

    }



    return 0;
}