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
		}
	}

	// TODO: always start with 1?
	timer := 1
	visit(1, &timer, childrenMap, timeRecordMap)
	for k, v := range timeRecordMap {
		fmt.Printf("%d %d %d\n", k+1, v.discoverTime, v.finishTime)
	}
}

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: # DFS(再帰） v:頂点
def DFS(v,dis,fin):
  global time
  # 訪問したので発見時刻を記入
  dis[v] = time
  time += 1
  
  # vに隣接している頂点をみる
  for u in V[v]:
    if dis[u] is None:
      DFS(u,dis,fin)
  
  # 処理が完了したので完了時刻を記入
  fin[v] = time
  time += 1
  
n = int(input())
# 0番目を始点として初期化
V = [[i for i in range(n)]]

for i in range(n):
  _, __, *a = map(int, input().split())
  V.append(a)

dis = [None]*(n+1)# 頂点を発見した時刻
fin = [None]*(n+1)# 頂点の完了時刻
time = 0
DFS(0,dis,fin)

for i in range(1,n+1):
  print(i, dis[i], fin[i])

Python: n = int(input())
M = [[0]*n for _ in range(n)]
st = [0]*n
d = [0]*n
f = [0]*n
tt = 0

def dfs(u,t):
    st[u] = 1
    t += 1
    d[u] = t
    for v in range(n):
        if M[u][v] == 0: continue
        if st[v] == 0: t = dfs(v,t)
    st[u] = 2
    t += 1
    f[u] = t
    return t

for _ in range(n):
    i = [int(i) for i in input().split()]
    u = i[0]
    k = i[1]
    V = i[2:]
    for v in V: M[u-1][v-1] = 1

for i in range(n):
    if st[i] == 0: tt = dfs(i,tt)

for i in range(n): print(i+1,d[i],f[i])

Python: import math,string,itertools,fractions,heapq,collections,re,array,bisect,sys,random,time,copy,functools
from collections import deque

sys.setrecursionlimit(10**7)
inf = 10**20
mod = 10**9 + 7

DR = [1, -1, 0, 0]
DC = [0, 0, 1, -1]

def LI(): return [int(x) for x in sys.stdin.readline().split()]
def LI_(): return [int(x)-1 for x in sys.stdin.readline().split()]
def LF(): return [float(x) for x in sys.stdin.readline().split()]
def LS(): return sys.stdin.readline().split()
def I(): return int(sys.stdin.readline())
def F(): return float(sys.stdin.readline())
def S(): return input()

N = I()
adj = [[] for _ in range(N)]
visited = [False for _ in range(N)]
d = [0 for _ in range(N)]
f = [0 for _ in range(N)]
cur_time = 1

for _ in range(N):
    edge_list = LI()
    u, k = edge_list[0], edge_list[1]
    if k == 0:
        continue
    v_list = edge_list[2:]
    u -= 1
    for v in v_list:
        v -= 1
        adj[u].append(v)

def dfs(u):
    global cur_time
    visited[u] = True
    for v in adj[u]:
        if not visited[v]:
            d[v] = cur_time
            cur_time += 1
            dfs(v)
    f[u] = cur_time
    cur_time += 1
    return

for v in range(N):
    if not visited[v]:
        d[v] = cur_time
        cur_time += 1
        dfs(v)

for v in range(N):
    print(v+1, d[v], f[v])

Python: n = int(input())
u = [list(map(int,input().split())) for _ in range(n)]
ts = [[0,0] for _ in range(n)]
time = 0

def dfs(i):
  global time
  ts[i][0] = time
  for j in range(u[i][1]):
    a = u[i][j+2]-1
    if ts[a][0] == 0:
      time += 1
      dfs(a)
  time += 1
  ts[i][1] = time
  
for i in range(n):
  if ts[i][0] == 0:
    time += 1
    dfs(i)
  
for i in range(n):
  print(i+1, ts[i][0], ts[i][1])

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 = [0] * 101
for i in range(n):
    data = input().split()
    V = list(map(int, data[2:]))
    V.sort(reverse = True)
    nodes[int(data[0])] = 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
        if len(node.V) == 0:
            node.finish_time = cnt
            cnt += 1
            del find_q[q_size -1]
            q_size = len(find_q)
        else:
            for x in node.V:
                if x in find_q:
                    find_q.remove(x)
                if nodes[x].finish_time == 0: 
                    find_q.append(x)
            q_size = len(find_q)

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

for i in range(1, n+1):
    if not isinstance(nodes[i], int):
        print(i, nodes[i].find_time, nodes[i].finish_time)

Python: 
def DFS(i):
    for j in range(n):
        if A[i][j] == 1 and d[j] == 0:
            time = time + 1
            d[j] = time
            DFS(j)
    time = time + 1
    f[i] = time

n = int(raw_input())
A = [0] * n
for i in range(n):
    A[i] = [0] * n

for i in range(n):
    value = map(int, raw_input().split())
    u = value[0] - 1
    k = value[1]
    nodes = value[2:]
    for i in range(k):
        v = nodes[i] - 1
        A[u][v] = 1

d = [0] * n
f = [0] * n
time = 1
d[0] = time
DFS(0)

for i in range(n):
    print(str(i + 1) + " " + str(d[0]) + " " + str(f[0]))

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)]
dfs(0, connect, visited, answer)
for v in range(v_num):
    print(*answer[v])

Python: from collections import deque
time = 1

def dfs(adj_list, d, f, color, u):

    global time
    S = list()

    S.append(u)
    color[u] = "G"
    d[u] = time
    time += 1

    while len(S) != 0:
        u = S[-1]

        if len(adj_list[u]) != 0:
            v = adj_list[u].popleft()

            if color[v] == "W":
                color[v] = "G"
                d[v] = time
                time += 1
                S.append(v)
        else:
            S.pop()
            color[u] = "B"
            f[u] = time
            time += 1

def Main():
    
    N = int(input())
    adj_list = [deque() for n in range(N)]
    d = [0] * N
    f = [0] * N
    color = [ "W" for i in range(len(d)) ]

    for n in range(N):
        u, k, *V = map(int, input().split())

        if k > 0:
            for i in V:
                adj_list[n].append(i - 1)

    while(True):

        ind = None
        for i in range(N):
            if color[i] == "W":
                ind = i
                break

        if ind == None:
            break
        else:
            dfs(adj_list, d, f, color, ind)

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

Main()