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: #Boost Force  / Backtracking
import sys
input = sys.stdin.readline
d = []
f = []
time = 0
#ทำการ search
def search(r):
    global d,f,time,s
    if d[r] == 0:
        time += 1
        d[r] = time
    else:
        return
    for x in s[r]:
        search(x)
    time += 1
    f[r] = time


n = int(input()) #รับค่าจำนวน node ทั้งหมด
s = [[] for i in range(n+1)]
for _ in range(n):
    d = list(map(int,input().split())) #รับข้อมูลทีละบรรทัด split เก็บเป็น int
    #ตน d[0] คือ node ตน 1 คือ ดีกรี ตนตั้งแต่ 2ไป คือ vertex
    s[d[0]] = d[2:]

d = [0 for _ in range(n+1)]
f = [0 for _ in range(n+1)]

for i in range(1,n+1):
    if d[i] == 0:
        search(i)

#แสดง node เวลาที่เจอ และ เวลา finish
for i in range(1,n+1):
    print (i,d[i],f[i])

Python: import sys
# sys.stdin = open('input.txt')

def fillMatrix():
    for i in range(n):
        u, k, *v = map(int, input().split())
        for j in v:
            matrix[i][j-1] = 1

def dfs(u):
    global time
    status[u] = VISITING
    time += 1
    discoverTime[u] = time
    for v in range(n):
        if matrix[u][v] and status[v] == NOT_VISITED:
            dfs(v)
    status[u] = VISITED
    time += 1
    finishTime[u] = time


n = int(input())
matrix = [[0]*n for i in range(n)]
time = 0
discoverTime = [0] * n
finishTime = [0] * n

NOT_VISITED = 0 # WHITE
VISITING = 1 # GRAY
VISITED = 2 # BLACK
status = [NOT_VISITED] * n

fillMatrix()
# Calling dfs(0) alone cannot reach nodes not connected from 0
for i in range(n):
    if status[i] != VISITED:
        dfs(i)

for i in range(n):
    ans = []
    ans.append(i+1)
    ans.append(discoverTime[i])
    ans.append(finishTime[i])
    ans = map(str, ans)
    print(' '.join(ans))

Python: # -*- coding: utf-8 -*-


class Graph:
    def __init__(self, n, adj_matrix):
        self.n = n
        self.g = adj_matrix

    def show(self):
        for _ in self.g:
            print(*_)

    def dfs(self, u, init=False):
        if init:
            self.states = [1] * self.n
            self.stack = []
            self.d = [None] * self.n
            self.f = [None] * self.n
            self.time = 0

        self.states[u] = 0
        self.time += 1
        self.d[u] = self.time

        for v, edge in enumerate(self.g[u]):
            if edge and self.states[v]:
                self.dfs(v)

        self.states[u] = 0
        self.time += 1
        self.f[u] = self.time

    def show_dfs(self, start=0):
        self.dfs(u=start, init=True)
        for i, (d, f) in enumerate(zip(self.d, self.f)):
            print(i + 1, d, f)


if __name__ == '__main__':
    n = int(input())
    adj_matrix = [[0] * n for i in range(n)]
    for i in range(n):
        for v in input().split()[2:]:
            adj_matrix[i][int(v) - 1] = 1

    g = Graph(n, adj_matrix)
    g.show_dfs()

Python: time = 1

class Vertex:
	def __init__(self, u, k):
		self.u = u
		self.vertices = [0] * k
		self.d = self.f = 0
	def __str__(self):
		return str(self.u) + ' ' + str(self.d) + ' ' + str(self.f)

def DFS(n, vertices):
	for i in range(n):
		if vertices[i].d == 0:
			DFS_(vertices, vertices[i].u)
			
def DFS_(vertitces, u):
	vertex = vertices[u-1]
	if vertex.d == 0:
		global time
		vertex.d = time
		time += 1
		for i in range(len(vertex.vertices)):
			DFS_(vertices, vertex.vertices[i])
		vertex.f = time
		time += 1
	
n = int(input())
vertices = []
for i in range(n):
	v = list(map(int, input().split()))
	u = v[0]
	k = v[1]
	vertex = Vertex(u, k)
	for j in range(k):
		vertex.vertices[j] = v[j+2]
	vertices.append(vertex)

DFS(n, vertices)
for i in range(n):
	print(str(vertices[i]))

Python: n = int(input())
l = [[] for i in range(n)]


class V:
    def __init__(self, node):
        self.d = -1
        self.f = -1
        self.node = node


for i in range(n):
    _input = [int(j) - 1 for j in input().split(" ")]
    u = _input[0]
    k = _input[1] + 1
    node = sorted(_input[2::])
    if u in node:
        node.remove(u)
    l[u] = V(node)

time = 1


def DFS(i):
    global time
    if l[i].d == -1:
        l[i].d = time
    time += 1
    for n in l[i].node:
        if l[n].d == -1:
            DFS(n)
            time+=1
    if l[i].f == -1:
        l[i].f = time
    return


for i in range(n):
    if l[i].d == -1:
        DFS(i)
        time+=1

for i, v in enumerate(l):
    print(i + 1, v.d, v.f)

Python: n = int(input())
g = [[] for i in range(n)]
for i in range(n):
    g[i] = list(map(lambda x:int(x)-1,input().split()))[2:]

def dfs(v,t):
    t += 1
    d[v] = t
    for i in g[v]:
        if d[i]==-1:
            t = dfs(i,t)
    t += 1
    f[v] = t
    return t

t = 0
d = [-1]*n
f = [-1]*n

for i in range(n):
    if d[i]==-1:
        t = dfs(i,t)

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

Python: N = input()
color = [0] * N
d = [0] * N
f = [0] * N
nt = [0] * N
m = [[0] * N for i in range(N)]
S = []
tt = 0

def next(u):
    w = nt[u]
    for v in range(w, N):
        nt[u] = v + 1
        if( m[u][v] ):
            return v
    return -1

def dfs_visit(r):
    global tt 
    S.append(r)
    tt += 1
    d[r] = tt

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

        v = next(u)
        if ( v != -1 ):
            if ( color[v] == 0 ):
                color[v] = 1
                tt += 1
                d[v] = tt
                S.append(v)
        else:
            S.pop()
            color[u] = 2
            tt += 1
            f[u] = tt

def dfs():
    for u in range(N):
        if( color[i] == 0 ):
            dfs_visit(u)

if __name__ == '__main__':

    for i in range(N):
        v = map(int, raw_input().split())
        for j in v[2:]:
            m[i][j-1] = 1
    
    dfs()

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