Go: package main

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

var sc = bufio.NewScanner(os.Stdin)
var depth [101]int
var finish [101]int
var d [101]int
var n, time int

func nextInt() int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return i
}
func visit(graph [][]int, u int) {
	depth[u] = 1
	time++
	d[u] = time
	for i := 0; i < n; i++ {
		if graph[u][i] == 1 {
			if depth[i] == 0 {
				visit(graph, i)
			}
		}
	}
	depth[u] = 2
	time++
	finish[u] = time
}
func main() {
	sc.Split(bufio.ScanWords)

	n = nextInt()
	graph := make([][]int, n)
	for i := 0; i < n; i++ {
		graph[i] = make([]int, n)
	}
	for i := 0; i < n; i++ {
		s := nextInt()
		t := nextInt()
		if t == 0 {
			continue
		}
		for i := 0; i < t; i++ {
			u := nextInt()
			graph[s-1][u-1] = 1
		}
	}
	for i := 0; i < n; i++ {
		if depth[i] == 0 {
			visit(graph, i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, d[i], finish[i])
	}
}

Python: n=int(input())
adj=[]
for i in range(n):
      adj.append(list(map(int, input().split())))

edge=[[0 for i2 in range(n)]for i1 in range(n)]

#??£??\???????????????

for i in range(n):
    for j in range(adj[i][1]):
        edge[i][adj[i][j+2]-1]=1


time=1
discover=[0 for i in range(n)]
final=[0 for i in range(n)]
stack=[]

def dfs(id,time):
    for i in range(n):
        c=0
        if edge[id][i]==1 and discover[i]==0:
            stack.append(id)
            discover[i]=time
            c+=1
            #print(discover,final,i,stack)
            dfs(i,time+1)
        else:
            pass
    if c==0:
        if len(stack)>0:
            if final[id]==0:
                final[id] = time
                #print("back",discover,final,id,stack)
                dfs(stack.pop(), time + 1)
            else:
                #print("back", discover, final, id, stack)
                dfs(stack.pop(),time)

discover[0]=time
stack.append(0)
dfs(0,time+1)


for i in range(n):
    if discover[i]==0:
        discover[i]=final[0]+1
        stack.append(i)
        dfs(i,final[0]+2)
        break

for i in range(n):
    print(i+1,discover[i],final[i])

Python: # 深さ優先探索 Depth first search: DFS


def dfs(u):
    global time
    color[u - 1] = 0
    time += 1
    d[u - 1] = time
    for v in range(1, n + 1):
        if A[u - 1][v - 1] == 1 and color[v - 1] == -1:
            dfs(v)
    color[u - 1] = 1
    time += 1
    f[u - 1] = time


n = int(input())
A = [[0 for i in range(n)] for i in range(n)]
for i in range(n):
    dat = [int(j) for j in input().split()]
    for j in range(dat[1]):
        A[dat[0] - 1][dat[2 + j] - 1] = 1

color = [-1 for i in range(n)]
d = [-1 for i in range(n)]
f = [-1 for i in range(n)]
time = 0
for i in range(n):
    if color[i] == -1:
        dfs(i+1)

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

Python: n = int(input())
graph = [[] for _ in range(n)]
for i in range(n):
    in_list = list(map(int, input().split()))
    u = in_list[0]
    graph[u - 1] = in_list[2:]

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

def dfs(now, prev, graph, d, f):
    if d[now] != 0:
        return d, f
    global time
    time += 1
    d[now] = time
    if not graph[now]:
        f[now] = time + 1
        time += 1
        return
    for k in graph[now]:
        if k - 1 == prev or d[k-1] !=0:
            continue
        dfs(k - 1, now, graph, d, f)
    else:
        time += 1
        f[now] = time
    return d, f



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

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:
            for x in node.V:
                if nodes[x].is_finded == False:
                    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
        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)

Python: import sys


def dfs(u):
    global time
    color[u] = "GRAY"
    time += 1
    d[u] = time
    for v in range(n):
        if M[u][v] and color[v] == "WHITE":
            dfs(v)
    color[u] = "BLACK"
    time += 1
    f[u] = time


if __name__ == "__main__":
    n = int(sys.stdin.readline())
    color = ["WHITE"] * n
    time = 0
    d = [-1] * n
    f = [-1] * n
    M = [[0] * n for i in range(n)]
    for inp in sys.stdin.readlines():
        inp = list(map(int, inp.split()))
        for i in inp[2:]:
            M[inp[0]-1][i-1] = 1
    for i in range(n):
        if d[i] == -1:
            dfs(i)
    for i in range(n):
        print(i+1, d[i], f[i])

Python: #coding:utf-8
from copy import deepcopy

n = int(input())
c = ["white" for i in range(n)]
d = [0 for i in range(n)]
f = [0 for i in range(n)]
S = []
class DFS:
    def __init__(self, key, color="white",nex=None):
        self.color = color
        self.nex = nex
        self.key = key

objListCopy = [DFS(i+1) for i in range(n)]
for i in range(n):
    data = list(map(int,input().split()))
    times = data[1]
    obj = objListCopy[i]
    for j in range(times):
        index = data[2+j] - 1
        nextobj = DFS(index+1)
        obj.nex = nextobj
        obj = obj.nex


time = 1
objList = objListCopy[:]
def check(first,time):
    obj = objList[first]
    c[first] = "gray"
    d[first] = time
    f[first] = time
    S.append(first+1)
    
    while S != []:
        index = S[-1] - 1
        u = objList[index]
        v = u.nex
        
        time += 1
        if v != None:
            if c[v.key - 1] == "white":
                objList[index] = v
                index = v.key - 1
                v = objList[index]
                c[v.key-1] = "gray"
                d[index] = time
                S.append(v.key)

            else:
                objList[index] = v
                time -= 1
                
        else:
            S.pop()
            c[u.key-1] = "black"
            f[index] = time
    return time


for i in range(n):
    if f[i] == 0:
        objList = deepcopy(objListCopy)
        time = check(i,time) + 1
        

k = 1
for i,j in zip(d,f):
    print(k,i,j)
    k += 1