Go: package main

import "fmt"

type node struct {
	id, d, v int
	adj      []node
}

var n int
var seen []bool
var graph []node

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

func dfs(v, t int) int {
	// fmt.Printf("dfs(v %d, t %d) en:\n", v, t)
	seen[v] = true
	graph[v].v = t
	tt := t
	for _, vv := range graph[v].adj {
		if !seen[vv.id] {
			tt = max(tt, dfs(vv.id, tt+1))
		}
	}
	graph[v].d = tt + 1
	// fmt.Printf("dfs(v %d, t %d) ex: d %d\n", v, t, graph[v].d)
	return graph[v].d
}

func main() {
	fmt.Scan(&n)
	graph = make([]node, n+1)
	for i := 1; i <= n; i++ {
		var u, k, v int
		fmt.Scan(&u, &k)
		graph[u].id = u
		// 頂点uはk個の隣接頂点を持っている
		for j := 0; j < k; j++ {
			fmt.Scan(&v)
			var t node
			t.id = v
			graph[u].adj = append(graph[u].adj, t)
		}
	}
	// fmt.Println("n", n, "graph", graph)
	seen = make([]bool, n+1)
	// t := dfs(1, 1)
	v, t := 1, 1
	done := false
	for !done {
		tt := dfs(v, t)
		done = true
		for i := range seen {
			if !seen[i] {
				done = false
				v = graph[i].id
				t = tt
				break
			}
		}
	}
	for i := 1; i <= n; i++ {
		fmt.Printf("%d %d %d\n", i, graph[i].v, graph[i].d)
	}
}

Python: class Vertex:
    def __init__(self,key):
        self.id = key
        self.connectedTo = {}
        self.color = 'white'
        self.dist =10000000
        self.pred = None
        self.disc = 0
        self.fin = 0
    
    def addNeighbor(self,nbr,weight=0):
        self.connectedTo[nbr] = weight

    def setColor(self,color):
        self.color = color

    def setDistance(self,d):
        self.dist = d

    def setPred(self,p):
        self.pred = p

    def setDiscovery(self,dtime):
        self.disc = dtime
        
    def setFinish(self,ftime):
        self.fin = ftime
        
    def getFinish(self):
        return self.fin
        
    def getDiscovery(self):
        return self.disc
        
    def getPred(self):
        return self.pred
        
    def getDistance(self):
        return self.dist
        
    def getColor(self):
        return self.color

    def getConnections(self):
        return self.connectedTo.keys()

    def getWeight(self,nbr):
        return self.connectedTo[nbr]

    def __str__(self):
        return str(self.id) + ' connectedTo: ' + str([x.id for x in self.connectedTo])

    def getId(self):
        return self.id


class Graph:
    def __init__(self):
        self.vertList = {}
        self.costList={}
        self.numVertices = 0

    def addVertex(self,key):
        self.numVertices = self.numVertices + 1
        newVertex = Vertex(key)
        self.vertList[key] = newVertex
        return newVertex

    def getVertex(self,n):
        if n in self.vertList:
            return self.vertList[n]
        else:
            return None

    def __contains__(self,n):
        return n in self.vertList

    def addEdge(self,f,t,cost=0):
        if f not in self.vertList:
            nv = self.addVertex(f)
        if t not in self.vertList:
            nv = self.addVertex(t)
        self.vertList[f].addNeighbor(self.vertList[t], cost)

    def getVertices(self):
        return self.vertlist.keys()

    def __iter__(self):
        return iter(self.vertList.values())


class DFSGraph(Graph):
	def __init__(self):
		super().__init__()
		self.time = 0

	def dfs(self):
		for aVertex in self:
			aVertex.setColor('white')
			aVertex.setPred(-1)
		for aVertex in self:
			if aVertex.getColor() == 'white':
				self.dfsvisit(aVertex)

	def dfsvisit(self,startVertex):

		for aVertex in self:
			aVertex.setColor('white')
			aVertex.setPred(-1)

		startVertex.setColor('gray')
		self.time += 1
		startVertex.setDiscovery(self.time)
		for nextVertex in startVertex.getConnections():
			if nextVertex.getColor() == 'white':
				nextVertex.setPred(startVertex)
				self.dfsvisit(nextVertex)
		startVertex.setColor('black')
		self.time += 1
		startVertex.setFinish(self.time)

Python: 
#graphの頂点vertex(インデックス、0オリジン)を深さ優先探索。dis_time:最初に訪れた時のtimeを管理するリスト
#fin_time:その頂点に対して、探索が終わった時のtimeを管理するリスト　tmp_time:現在のtime(関数内で変更できるようにリスト)
def DPS(graph,vertex,dis_time,fin_time,tmp_time):
    dis_time[vertex]=tmp_time[0]
    for i in range(len(graph[0])):
        if(graph[vertex][i] !=0 and dis_time[i]==0):#枝先の頂点が探索済みでなかったら、
            tmp_time[0]+=1
            DPS(graph,i,dis_time,fin_time,tmp_time)
    
    if(dis_time[vertex]==tmp_time[0]):#vertexから、どの頂点に対しても調査が進まなかったら
        tmp_time[0]+=1
    fin_time[vertex]=tmp_time[0]
    tmp_time[0]+=1



#グラフの作成
n=int(input())
graph=[[0]*n for loop in range(n)]
for loop in range(n):
    tmp_ope=list(map(int,input().split()))
    for j in range(tmp_ope[1]):
        graph[tmp_ope[0]-1][tmp_ope[j+2]-1]=1

dis_time=[0]*n
fin_time=[0]*n
tmp_time=[1]
DPS(graph,0,dis_time,fin_time,tmp_time)

for i in range(n):
    print(f"{i+1} {dis_time[i]} {fin_time[i]}")

Python: def DFS(s, t):
    t += 1
    flag[s] = 1
    d[s] = t
    for i in range(1, n+1):
        if G[s][i] == 1:
            if flag[i] == 0:
                DFS(i, t)
                t = f[i]
    f[s] = t + 1

n = int(raw_input())
G = [[0 for i in range(n+1)] for j in range(n+1)]
d = [0 for i in range(n+1)]
f = [0 for i in range(n+1)]

for i in range(n):
    v = map(int, raw_input().split())
    for j in range(v[1]):
        G[v[0]][v[2+j]] = 1

flag = [0 for i in range(n+1)]
for i in range(1, n+1):
    if flag[i] == 0:
        DFS(i, max(f))

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

Python: WHITE = 0
GRAY = 1
BLACK = 2
color, d, f = [WHITE for i in range(n)]
t = 1

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

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

Python: from collections import defaultdict

def dfs(here, connect, visited, answer):
    global time
    answer[here][1] = time
    time += 1
    visited[here] = 1
    for c in connect[here]:
        if not visited[c]:
            dfs(c, connect, visited, answer)
    answer[here][2] = time
    time += 1

v_num = int(input())
connect = defaultdict(list)
for _ in range(v_num):
    inp = [int(n) - 1 for n in input().split(" ")]
    connect[inp[0]].extend(inp[2:])
answer = [[n + 1 for m in range(3)] for n in range(v_num)]
time = 1
visited = [0 for n in range(v_num)]
dfs(0, connect, visited, answer)
for v in range(v_num):
    print(*answer[v])

Python: N = int(input())
edge = [[0] for _ in range(N)]
for i in range(N):
    A = list(map(int, input().split()))
    for i,a in enumerate(A):
        A[i] -= 1
    edge[A[0]] = sorted(A[2:])
ans = [[0,0] for _ in range(N)]
import sys
sys.setrecursionlimit(10**8)

def dfs(v,now):
    if len(edge[v])>0:
        for u in edge[v]:
            if visited[u]==False:
                visited[u]=True
                now += 1
                ans[u][0] = now
                now = dfs(u,now)
    now += 1
    ans[v][1] = now
    return now

visited = [False]*N

now = 0
for i in range(N):
    if visited[i]==False:
        visited[i]=True
        now += 1
        ans[i][0] = now
        now = dfs(i,now)
for i in range(N):
    ans[i] = '{} {} {}'.format(i+1,ans[i][0],ans[i][1])
print(*ans,sep='\n')