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())
}

Python: class Node(object):
    def __init__(self, V):
        self.V = V
        self.find_time = 0
        self.finish_time = 0
        self.is_finded = False

n = int(input())
nodes = []
nodes.append(Node([]))

for i in range(n):
    data = input().split()
    V = list(map(int, data[2:]))
    nodes.append(Node(V))

find_q = []
find_q.append(1)
cnt = 1
q_size = len(find_q)
while q_size != 0:
    #print(find_q)
    node = nodes[find_q[q_size -1]]

    if node.is_finded == False:
        node.find_time = cnt
        cnt += 1
        node.is_finded = True
    else:   #node is finded
        node.finish_time = cnt
        cnt += 1
        del find_q[q_size -1]
        q_size = len(find_q)
        continue

    if len(node.V) == 0:
        node.finish_time = cnt
        cnt += 1
        del find_q[q_size -1]
        q_size = len(find_q)
    else:
        find_q.extend(node.V)
        q_size = len(find_q)

for i,x in enumerate(nodes):
    if i == 0:
        continue
    print(i, x.find_time, x.finish_time)

Python: import heapq
from collections import deque
from enum import Enum
import sys
import math
from _heapq import heappush, heappop

BIG_NUM = 2000000000
MOD = 1000000007
EPS = 0.000000001

global current_time
global visited,go_time,back_time
global G


def dfs(node_id):
    global current_time #書かないとローカル変数扱いされる
    go_time[node_id] = current_time
    current_time += 1

    for next_node in G[node_id]:

        if visited[next_node] == True:
            continue
        visited[next_node] = True
        dfs(next_node)

    back_time[node_id] = current_time
    current_time += 1


V = int(input())

G = [[] for i in range(V)]

visited = [False]*V

go_time = [0]*V
back_time = [0]*V

for loop in range(V):
    node_id,num,*tmp_adj = list(map(int,input().split()))
    node_id -= 1
    for i in range(num):
        G[node_id].append(tmp_adj[i]-1)

current_time = 1;

for i in range(V):
    if visited[i] == True:
        continue
    visited[i] = True
    dfs(i)

for i in range(V):
    print("%d %d %d"%(i+1,go_time[i],back_time[i]))

Python: #!/usr/bin/env python
from __future__ import division, print_function
from sys import stdin


def walk(index, tm, L, d, f):
    tm += 1
    d[index] = tm
    for i in L[index]:
        if not d[i-1]:
            tm = walk(i-1, tm, L, d, f)
    tm += 1
    f[index] = tm
    return tm


def main():
    num = int(stdin.readline())

    L = []
    for _ in xrange(num):
        L.append([int(s) for s in stdin.readline().split()[2:]])

    d = [0] * num
    f = [0] * num
    walk(0, 0, L, d, f)

    for i in xrange(num):
        print(i+1, d[i], f[i])


main()

Python: def d(u):
 global t
 C[u]=0;D[u]=t;t+=1
 for v in M[u]:v=int(v)-1;C[v]and d(v)
 F[u]=t;t+=1
N=int(input());R=range(N)
M=[input().split()[2:]for _ in R]
C,D,F=[1]*N,[0]*N,[0]*N
t=1
for i in R:C[i]and d(i)
for i in R:print(i+1,D[i],F[i])

Python: from collections import defaultdict

def dfs(here, connect, visited, answer):
    global time
    answer[here][1] = time
    time += 1
    visited[here] = 1
    for c in connect[here]:
        if not visited[c]:
            dfs(c, connect, visited, answer)
    answer[here][2] = time
    time += 1

v_num = int(input())
connect = defaultdict(list)
for _ in range(v_num):
    inp = [int(n) - 1 for n in input().split(" ")]
    connect[inp[0]].extend(sorted(inp[2:]))
answer = [[n + 1 for m in range(3)] for n in range(v_num)]
time = 1
visited = [0 for n in range(v_num)]
for i in range(v_num):
    if not visited[i]:
        dfs(i, connect, visited, answer)
for v in range(v_num):
    print(*answer[v])

Python: # coding=utf-8

n = int(input())
first_v = 0
time = 0
L = []
d = [None for _ in range(n)]
f = [None for _ in range(n)]
stuck = []
for _ in range(n):
    u, k, *v = map(int, input().split())
    L.append(list(map(lambda x: x-1, v)))

v = first_v #??¢?´¢????????????
while True:
    """print("------------------------------")
    print("stuck:", *stuck)
    print("L:", L)
    print("d:", *d)
    print("f:", *f)
    print("time:", time)
    print("v:", v)"""
    if len(L[v]) > 0:
        stuck.append(v)
        if not d[v]:
            time += 1
            d[v] = time
        v = L[v].pop(0)
    elif len(stuck) > 0:
        if not d[v]:
            time += 1
            d[v] = time
        if not f[v]:
            time += 1
            f[v] = time
        v = stuck.pop(-1)
    else:
        time += 1
        f[first_v] = time
        break

for i in range(n):
    print("{} {} {}".format(i+1, d[i], f[i]))