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: n = int(input())
graph = {}
ans = []
np = set(range(1,n+1))
for i in range(n):
    t = list(map(int, input().split()))
    v = t[0]
    k = t[1]
    graph[v] = [t[i+2] for i in range(k)]
    np=np - set(graph[v])
    ans.append([v,None,None])

class Time:
    def __init__(self):
        self.time = 0
    def getTime(self):
        self.time += 1
        return self.time

t = Time()

visited = set()
def dfs(graph, target):
    visited.add(target)
    # ???????????????????¨????
    if ans[target - 1][1] is None:
        ans[target - 1][1] = t.getTime()
    if graph[target] == []:
        if ans[target - 1][2] is None:
            ans[target - 1][2] = t.getTime()        
        return
    for v in sorted(graph[target]):
        # # ???????????????????¨????
        if v not in visited:        
            if ans[v - 1][1] is None:
                ans[v - 1][1] = t.getTime()        
            visited.add(target)
            dfs(graph,v)
    if ans[target - 1][2] is None:
        ans[target - 1][2] = t.getTime()

for v in np:
    dfs(graph,v)
for row in ans:
    print(*row)

Python: # -*- coding: utf-8 -*-
import sys
sys.setrecursionlimit(100000)
N = int(input())
adj = [[0]*N for _ in range(N)]
searched = {n: 0 for n in range(N)}
edge = {}

for n in range(N):
    inp = list(map(int, input().split()))
    edge[n] = inp[1]
    for i in inp[2:]:
        adj[inp[0]-1][i-1] = 1

time = 1
stack = []
unsearch = set(range(N))
uncomplete = set(range(N))
result = {n:{"found": 0, "finish": 0} for n in range(N)}

def DFS(i):
    global time
    global unsearch
    
    itr = sorted(unsearch)
    
    for j in itr:
        if adj[i][j] == 1 and j in unsearch:
            result[j]["found"] = time
            time += 1
            unsearch.remove(j)
            DFS(j)
    result[i]["finish"] = time
    time += 1
    
while len(unsearch):
    i = min(unsearch)
    unsearch.remove(i)
    result[i]["found"] = time
    time += 1
    DFS(i)

for n in range(N):
    print("{} {} {}".format(n+1, result[n]["found"], result[n]["finish"]))

Python: # coding: utf-8

visited = [False]*101
discovery_time = [0]*101
finish_time = [0]*101
A = [[] for _ in range(101)]
time = 0

def dfs(n):
    global time
    if visited[n] == True:
        return
    time += 1
    discovery_time[n] = time
    visited[n] = True
    for i in A[n]:
        dfs(i)
    time += 1
    finish_time[n] = time

n = int(input().rstrip())
for i in range(n):
    line = [int(j) for j in input().rstrip().split()]
    A[i+1].extend(line[2:])

for i in range(n):
    dfs(i+1)
    
for i in range(n):
    print(str(i+1)+ " "+ str(discovery_time[i+1])+" "+str(finish_time[i+1]))

Python: #coding: utf-8

n = int(input())
color = ["white" for i in range(n)]
d = [[] for i in range(n)]
global t
t = 0
M = [[False for i in range(n)] for j in range(n)]
for i in range(n):
    data = list(map(int,input().split()))
    u = data[0]
    k = data[1]
    if i == 0:
        start = u
    for v in data[2:2+k]:
        M[u-1][v-1] = True


def search(u,t):
    t += 1
    color[u-1] = "gray"
    d[u-1].append(t)
    for v in range(n):
        if M[u-1][v-1] and color[v-1] == "white":
            t = search(v,t)
    color[u-1] = "black"
    t += 1
    d[u-1].append(t)
    return t

t = search(start, t)
for i in range(n):
    if color[i-1] == "white":
        t += 1
        t = search(i, t)

for i in range(n):
    print(i+1, d[i][0], d[i][1])

Python: 
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: n = int(input())
G = []
checked = [False for i in range(n + 1)]
d = [0 for i in range(n + 1)]
f = [0 for i in range(n + 1)]
G.append([])
for i in range(n):
    u, k, *v = map(int, input().split())
    G.append(v)

timestamp = 1

def dfs(id):
    global timestamp

    checked[id] = True
    d[id] = timestamp
    timestamp += 1
    for v in G[id]:
        if not checked[v]:
            dfs(v)
    f[id] = timestamp
    timestamp += 1

for id in range(1, n + 1):
    if not checked[id]:
        dfs(id)

for i in range(1, n + 1):
    print("{0} {1} {2}".format(i, d[i], f[i]))