Go: package main

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

type vertexId int

type vertex struct {
	id vertexId
	firstVisitAt int
	finishVisitAt int
	adjs []vertexId
}

func createVertex(id int, adjsInt []int) vertex {
	adjs := make([]vertexId, len(adjsInt))
	for i := 0; i < len(adjs); i++ {
		adjs[i] = vertexId(adjsInt[i])
	}
	return vertex{
		id: vertexId(id),
		firstVisitAt: 0,
		finishVisitAt: 0,
		adjs: adjs,
	}
}

func (v *vertex) doesAllAdjsVisited(vertices []vertex) bool {
	for _, vId := range v.adjs {
		adj := vertices[vId-1]
		if !adj.isVisited() {
			return false
		}
	}
	return true
}

func (v *vertex) isFirstVisit() bool {
	return v.firstVisitAt == 0
}

func (v *vertex) isVisited() bool {
	return v.firstVisitAt > 0
}

func (v *vertex) nextVertex(vertices []vertex) (vertexId, error) {
	for _, vId := range v.adjs {
		adj := vertices[vId-1]
		if !adj.isVisited() {
			return vId, nil
		}
	}
	return vertexId(-1), fmt.Errorf("illegal")
}

func dfs(currentId vertexId, timestamp int, vertices []vertex) int {
	timestamp = timestamp + 1
	currentVertex := &vertices[currentId-1]
	if currentVertex.isFirstVisit() {
		currentVertex.firstVisitAt = timestamp
	}
	for !currentVertex.doesAllAdjsVisited(vertices) {
		nextVertexId, _ := currentVertex.nextVertex(vertices)
		timestamp = dfs(nextVertexId, timestamp, vertices)
	}
	timestamp = timestamp + 1
	currentVertex.finishVisitAt = timestamp
	return timestamp
}

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	n, err := nextInt(sc)
	if err != nil {
		panic(err)
	}

	vertices := make([]vertex, n)
	for i := 0; i < n; i++ {
		id, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjN, err := nextInt(sc)
		if err != nil {
			panic(err)
		}
		adjs := make([]int, adjN)
		for j := 0; j < adjN; j++ {
			adjId, err := nextInt(sc)
			if err != nil {
				panic(err)
			}
			adjs[j] = adjId
		}
		vertices[i] = createVertex(id, adjs)
	}

	dfs(vertexId(1), 0, vertices)

	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", vertices[i].id, vertices[i].firstVisitAt, vertices[i].finishVisitAt)
	}
}

func nextText(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func nextInt(sc *bufio.Scanner) (int, error) {
	return strconv.Atoi(nextText(sc))
}

Python: n=int(input())

next=[[] for i in range(n)]
for i in range(n):
	l=list(map(int,input().split()))
	u=l[0]
	k=l[1]
	for j in range(2,k+2):
		next[u-1].append(l[j]-1)

stk=[]
stk.append(0)
print(next)
time=1
d=[0 for i in range(n)]
f=[0 for i in range(n)]
while(len(stk)!=0):
	if len(next[stk[-1]])==0:
		if d[stk[-1]]==0:
			d[stk[-1]]=time
			#print(stk[-1])
			time+=1
		f[stk[-1]]=time
		#print(stk[-1])
		time+=1
		stk.pop()
	else:
		v=min(next[stk[-1]])
		if d[v]!=0:
			next[stk[-1]].remove(v)
		else:
			if d[stk[-1]]==0:
				d[stk[-1]]=time
				time+=1
			#print(stk[-1])
			next[stk[-1]].remove(v)
			stk.append(v)
			

for i in range(n):
	out=[]
	out.append(i+1)
	out.append(d[i])
	out.append(f[i])
	print(*out)

Python: n = int(input())
al = [list(map(lambda s: int(s) - 1, input().split()))[2:] for _ in range(n)]
begin = [-1] * n
end = [-1] * n
not_visited = list(range(n))
t = 1
def dfs(u):
    global begin, end, t, not_visited
    begin[u] = t
    t += 1
    not_visited.remove(u)
    for v in al[u]:
        if begin[v] == -1:
            dfs(v)
    end[u] = t
    t += 1

while len(not_visited) > 0:
    dfs(not_visited[0])

for i in range(n):
    print('{} {} {}'.format(i + 1, begin[i], end[i]))

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

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

WHITE = 0
GRAY = 1
BLACK = 2
color, d, f = [WHITE for i in range(n)]
t = 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: def dfs(u, colors, matrix, time, detect_time, finished_time):
    # ????????????????????¨??????????????????
    colors = colors
    detect_time = detect_time
    finished_time = finished_time
    time = time + 1
    stack = list()
    stack.append(u)
    colors[u] = 1
    detect_time[u] = time
    while len(stack):
        for i, val in enumerate(matrix[u]):
            if val == 1 and colors[i] == 0:
                time += 1
                stack.append(i)
                colors[i] = 1
                detect_time[i] = time
                u = i
                break
        else:
            time += 1
            e = stack.pop()
            colors[e] = 2
            finished_time[e] = time
            if len(stack):
                u = stack[-1]
    return time


if __name__ == '__main__':
    N = int(input())
    matrix = [[0] * N for _ in range(N)]
    color = [0] * N
    for i in matrix:
        node_info = [int(i) for i in input().split()]
        node_i = node_info[0] - 1
        if not node_info[1] == 0:
            for i in node_info[2:]:
                matrix[node_i][i - 1] = 1
    colors = [0] * len(matrix)
    detect_time = [0] * len(matrix)
    finished_time = [0] * len(matrix)
    time = 0
    for i, val in enumerate(colors):
        if val == 0:
            time = dfs(i, colors, matrix, time, detect_time, finished_time)

    for i in range(len(matrix)):
        print('{} {} {}'.format(i + 1, detect_time[i], finished_time[i]))

Python: #!/usr/bin/env python
# -*- coding:utf-8 -*-
from __future__ import division,print_function
import time
import sys
import io
import re
import math
start = time.clock()
i = 0
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(sys.stdin.readline())
    L=[]
    for _ in range(num):
        L.append([int(s) for s in sys.stdin.readline().split()[2:]])
    d=[0]*num
    f=[0]*num
    tm=0
    for i in range(num):
        if not d[i]:
            tm=walk(i,tm,L,d,f)
    for i in range(num):
        print(i+1,d[i],f[i])

main()

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
            find_q.pop()
            q_size = len(find_q)
        else:
            f = 0
            for x in node.V: 
                if nodes[x].is_finded == False:
                    f = 1
                    if x in find_q:
                        find_q.remove(x)
                    if nodes[x].finish_time == 0: 
                        find_q.append(x)
            
            if f == 0:  # didnt append nodes
                node.finish_time = cnt
                cnt += 1
                find_q.pop()
                q_size = len(find_q) 
            else :    
                q_size = len(find_q)
  
    else:   #node is finded 
        node.finish_time = cnt
        cnt += 1
        find_q.pop()
        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)