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: # coding: UTF-8
from collections import deque
#入力値の整理
n = int(input())
adj={}
visited={}
d={}
f={}
t=0
visited=set()
for i in range(n):
  raw=list(map(int,input().split()))
  u = raw.pop(0)
  k = raw.pop(0)
  raw.sort()
  q = deque(raw)
  adj[u] = q  
  d[u] = -1
  f[u] = -1

next = 1
v = next
d[next] = t + 1
stack = deque()
visited.add(v)

while True:
  t = t+1
  clear = True
  while adj[v]:
    cand = adj[v].popleft()
    if cand not in visited:
      next = cand
      d[next] = t + 1
      visited.add(next)
      clear = False
      break
  if clear:
    f[v] = t + 1
    if stack:
      next = stack.pop()
      v = next
    else:
      end = True
      for i in range(n):
        if i+1 not in visited:
          next = i+1
          end = False
          break
      if end:
        break
      else:
        t = t+1
        v = next
        d[next] = t + 1
        visited.add(v)
  else:
    stack.append(v)
    v = next

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

#return d,f

Python: n = int(input())
mat = [[0] * n for _ in range(n)]
d, f = [0] * n, [0] * n
for _ in range(n):
    adj = list(map(int, input().split()))
    i = adj[0]
    v = adj[2:]
    for j in v:
        mat[i - 1][j - 1] = 1

time, current = 1, 0
stack = []
d[current] = time
while 0 in f:
    if not stack:
        stack.append(0)
    time += 1
    current = stack[-1]
    for i in range(len(mat[current])):
        if mat[current][i] and not d[i]:
            current = i
            d[i] = time
            stack.append(i)
            break
    else:
        f[current] = time
        current = stack.pop()

for l in zip(range(1, n + 1), d, f):
    print(*l)

Python: from collections import deque

#スタックを使った深さ優先探索の実装
l = int(input())
rlist = []
for i in range(l):
    li = list(map(int, input().split()))
    rlist.append(deque([ll-1 for ll in li[2:]]))


color = ['white'] * l
find_time = [0] * l
stop_time = [0] * l
stack = []
time = 0

def dfs(u):
    global time

    stack.append(u)
    color[u] = 'gray'
    time += 1
    find_time[u] = time

    while len(stack) > 0:
        #print(stack)
        #print(color)
        #print(rlist)

        u = stack[-1]
        #頂点uにまだ訪問すべき頂点が残っているなら
        if len(rlist[u]) > 0:
            if color[rlist[u][0]] == 'white':
                time += 1
                find_time[rlist[u][0]] = time
                color[rlist[u][0]] = 'gray'
                stack.append(rlist[u][0])
            rlist[u].popleft()
        #頂点uにもう訪問すべき頂点が残っていないなら
        else:
            time += 1
            stop_time[u] = time
            color[u] = 'black'
            stack.pop()

for i in range(l):
    if color[i] == 'white':
        dfs(i)
for i in range(len(find_time)):
    print(str(i+1) + ' ' + str(find_time[i]) + ' ' + str(stop_time[i]))

Python: def depth_search(u, t):
    t += 1
    s.append(u)
    d[u] = t
    for v in range(N):
        if adjacency_list[u][v] == 0:
            continue 
        if d[v] == 0 and v not in s:
            t = depth_search(v, t)
    t += 1
    s.pop()
    f[u] = t
    return t

N = int(input())
adjacency_list = [[0 for j in range(N)] for i in range(N)]
for _ in range(N):
    u, k, *v = input().split()
    for i in v:
        adjacency_list[int(u)-1][int(i)-1] = 1

s = []
d = [0 for _ in range(N)]
f = [0 for _ in range(N)]

t = 0
for u in range(N):
    if d[u] == 0:
        t = depth_search(u, t)

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

Python: def visit(u):
    global visit_color, d, f, t
    color[u] = GRAY
    d[u] += t
    t += 1
    for v in range(n):
        if (M[u][v] == 0):
            continue
        else:
            if (color[v] == WHITE):
                visit(v)
    color[u] = BLACK
    f[u] = t
    t += 1

n = int(input())
M = [[0 for i in range(n)] for i in range(n)]
for i in range(n):
    tmp = list(map(int, input().split()))
    for j in range(tmp[1]):
        M[tmp[0]-1][tmp[j+2]-1] = 1

for u in range(n):
    if (color[u] == WHITE):
        visit(u)
for u in range(n):
    print(str(u+1), str(d[u]), str(f[u]), sep = " ")

Python: from sys import stdin
n = int(stdin.readline())
M = [list(map(int, stdin.readline().split()[2:])) for i in range(n)]
sndf = [[False, i] for i in range(1, n + 1)]
tt = 0
def dfs(u):
    global tt
    sndf[u][0] = True
    tt += 1
    sndf[u].append(tt)
    for v in M[u]:
        v -= 1
        if not sndf[v][0]:
            dfs(v)
    tt += 1
    sndf[u].append(tt)
for i in range(0, n):
    if not sndf[i][0]:
        dfs(i)
    print(*sndf[i][1:])

Python:    #depth first
N=int(input())
V=[]
a=[0]
for i in range(N):
    V.append([int(i) for i in input().split()])
    w=V[i][2:]
    w.sort()
    V[i]=V[i][:2]+w
    a.append(0)
V=sorted(V,key=lambda x:x[0])
c=1
t=1
i=0
r=[1]
a[1]=1
p=[[1,t]]
q=[]
while t<N*2:
    j=2
    while t<N*2 and j-2<V[i][1] and V[i][1]>0 and a[V[i][j]]==1:
        j+=1
    t+=1
    if j-2<V[i][1]:
        a[V[i][j]]=1
        c+=1
        r.append(V[i][j])
        p.append([V[i][j],t])
        i=V[i][j]-1
    else:
        q.append(p[-1]+[t])
        r.pop(-1)
        p.pop(-1)
        if len(r)>0:
            i=r[-1]-1
        else:
            j=1
            while j<N and a[j]==1:
                j+=1
            if j<N:
                t+=1
                i=j-1
                r.append(j)
                p.append([j,t])
q=sorted(q,key=lambda x:x[0])
for i in range(N):
    for j in range(3):
        q[i][j]=str(q[i][j])
    print(" ".join(q[i]))

Python: def DFS(num):
    global time
    time +=1
    color[num]="gray"
    D[num][0]=time
    for i in M[num]:
        if color[i]=="white":
            DFS(i)
    color[num]="black"
    time +=1
    D[num][1]=time


n=int(input())
M=[[] for _ in range(n+1)]
for i in range(n):
    for j in list(map(int,input().split()))[2:]:
        M[i+1].append(j)
color=["white" for _ in range(n+1)]
D=[[0,0] for _ in range(n+1)]
time=0
for i in range(n):
    if color[i+1]=="white":
        DFS(i+1)

for i in range(n):
    print(i+1,*D[i+1])