Go: package main

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

var scanner = bufio.NewScanner(os.Stdin)

func nextString() string {
	scanner.Scan()
	return scanner.Text()
}

func nextInt() int {
	n, err := strconv.Atoi(nextString())
	if err != nil {
		fmt.Printf("strconv.Atoi failed: %v\n", err)
	}
	return n
}

var infty = 1000000000

type nodeKey int

type DirectedGraphNode struct {
	key       nodeKey
	adjacents []*DirectedGraphNode
	visited   bool
	d         int
	f         int
	parent    *DirectedGraphNode
}

type DirectedGraph struct {
	nodes []*DirectedGraphNode
}

func (g *DirectedGraph) setAdjacency(l, r nodeKey) {
	g.nodes[l].adjacents = append(g.nodes[l].adjacents, g.nodes[r])
}

func newDirectedGraph(nNodes int) *DirectedGraph {
	graph := DirectedGraph{}
	graph.nodes = make([]*DirectedGraphNode, nNodes)
	for iNodes := 0; iNodes < nNodes; iNodes++ {
		graph.nodes[iNodes] = &DirectedGraphNode{}
		graph.nodes[iNodes].key = nodeKey(iNodes)

		graph.nodes[iNodes].visited = false
		graph.nodes[iNodes].d = infty
		graph.nodes[iNodes].f = infty
		graph.nodes[iNodes].parent = nil
	}
	return &graph
}

type QueueEntry struct {
	node *DirectedGraphNode
	next *QueueEntry
}

type Queue struct {
	head, tail *QueueEntry
}

func (q *Queue) enqueue(node *DirectedGraphNode) {
	entry := QueueEntry{}
	entry.node = node

	if q.tail == nil {
		q.head = &entry
		q.tail = &entry
		return
	}

	q.tail.next = &entry
	q.tail = q.tail.next
}

func (q *Queue) dequeue() *QueueEntry {
	if q.head == nil {
		return nil
	}
	poped := q.head
	q.head = q.head.next
	if q.head == nil {
		q.tail = nil
	}
	return poped
}

func (q *Queue) isEmpty() bool {
	return q.head == nil
}

var time = 0

func fillDistancesByDepthFirstSearch(g *DirectedGraph) {
	for _, u := range g.nodes[1:] {
		if !u.visited {
			dfsVisit(g, u)
		}
	}
}

func dfsVisit(g *DirectedGraph, u *DirectedGraphNode) {
	time++
	u.d = time

	u.visited = true
	for _, v := range u.adjacents {
		if !v.visited {
			v.parent = u
			dfsVisit(g, v)
		}
	}
	time++
	u.f = time
}

func main() {
	scanner.Split(bufio.ScanWords)

	nNodes := nextInt()
	g := newDirectedGraph(nNodes + 1)

	for iNode := 0; iNode < nNodes; iNode++ {
		nodeKeyLeft := nodeKey(nextInt())
		nAdj := nextInt()
		for iAdj := 0; iAdj < nAdj; iAdj++ {
			nodeKeyRight := nodeKey(nextInt())
			g.setAdjacency(nodeKeyLeft, nodeKeyRight)
		}
	}

	fillDistancesByDepthFirstSearch(g)

	for iNode := 1; iNode <= nNodes; iNode++ {
		node := g.nodes[iNode]
		fmt.Println(node.key, node.d, node.f)
	}
}

Python: def dfs_recursive(u):
    global time
    color[u] = 'gray'
    arrive[u] = time
    time += 1
    for v in range(n):
        if adjMat[u][v] == 1 and color[v] == 'white':
            dfs_recursive(v)
    color[u] = 'black'
    finish[u] = time
    time += 1


n = int(input())

adjMat = [[0] * n for _ in range(n)]
color = ['white'] * n
arrive = [0] * n
finish = [0] * n
time = 1

for _ in range(n):
    adj = list(map(int, input().split()))
    i = adj[0]
    v = adj[2:]
    for j in v:
        adjMat[i - 1][j - 1] = 1

for root in range(n):
    if color[root] == 'white':
        dfs(root)


for i in range(n):
    out = ''
    out += '{} {} {}'.format(i + 1, arrive[i], finish[i])
    print(out)

Python: import sys
input = sys.stdin.readline
v = []
tl = []
t = 1

def rec(node):
	global t, tl, v
	if tl[node-1][0] != -1:
		# print("ret", node, tl[node-1][0])
		return
	tl[node-1][0] = t
	t += 1
	# print("t: {}", t)
	adj = v[node-1][2:]
	# print("adj: ", adj)
	for i in adj:
		rec(v[i-1][0])
	tl[node-1][1] = t
	t += 1

def main():
	global v, tl
	n = int(input().strip())
	tl = [[-1, -1] for _ in range(n)]
	for i in range(n):
		l = list(map(int, input().strip().split()))
		v.append(l)
	for i in range(1, n+1):
		rec(i)
	for i in range(n):
		print("{} {} {}".format(i+1, tl[i][0], tl[i][1]))

if __name__ == '__main__':
	main()

Python: 
def dfs_visit(u):
    global n, M, d, f, time

    if color[u] == 'WHITE':
        color[u] = 'GRAY'
        time += 1
        d[u] = time

        for v in range(n):
            if M[u][v] == 0:
                continue
            if color[v] == 'WHITE':
                dfs_visit(v)

        color[u] = 'BLACK'
        time += 1
        f[u] = time


def dfs():
    global n, M, d, f, time

    for u in range(n):
        if color[u] == 'WHITE':  # 連結グラフとは限らないため。
            dfs_visit(u)

    for u in range(n):
        print('{} {} {}'.format(u+1, d[u], f[u]))


n = int(input())

M = [[0 for i in range(n)] for j in range(n)]
color = ['WHITE'] * n  # 各頂点の色を記録。ホワイト（未探索）、グレイ（探索中）、ブラック（探索ずみ）
d = [None] * n  # vを最初に発見した時間
f = [None] * n  # vの完了時刻
time = 0

for i in range(n):
    _ = list(map(int, input().split()))
    u = _[0] - 1  # 0オリジンに変換

    degree = _[1]
    for j in range(degree):
        v = _[j+2] - 1  # 0オリジンに変換
        M[u][v] = 1

# for row in M:
#     print(' '.join(map(str, row)))

dfs()

Python: n = int(input())
A = [[0 for i in range(n)] for j in range(n)]

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

# for row in A:
#     msg = ' '.join(map(str, row))
#     # print(msg)

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

t = 0
d[0] = t

# recursive


def dfs(u):
    global t
    # print('visit:', str(u), str(t))
    t += 1
    d[u] = t
    for i in range(len(A[u])):
        if A[u][i] == 1 and d[i] == -1:
            dfs(i)
    t += 1
    f[u] = t
            


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


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

Python: n = int(input())
d = [0]*n
f = [0]*n
G = [[] for _ in range(n)]
for _ in range(n):
    l = list(map(int, input().split()))
    u, k = l[:2]
    l = list(map(lambda x: x-1, l[2:]))
    G[u-1] = l

timestamp = [i+1 for i in range(2*n)]
def dfs(node):
    global d,f,G,timestamp
    if d[node]>0:
        return False
    d[node] = timestamp.pop(0)
    for v in G[node]:
        dfs(v)
    if f[node]==0:
        f[node] = timestamp.pop(0)
    return True
for i in range(n):
    dfs(i)
    
for i in range(n):
    print(i+1, d[i], f[i])

Python: def dfs(vum,v,d,f,t):
    # print('first')
    # print(vum,v,d,f,t)
    if f[v] >= 0:
        return d,f,t
    t += 1
    d[v] = t
    for u in vum[v]:
        # print(v, d[v], f[v], u, d[u], f[u])
        if d[u] >= 0:
            # print('skip', str(v), str(u))
            continue
        d,f,t = dfs(vum,u,d,f,t)
    t += 1
    f[v] = t
    # print(v, d[v], f[v])
    # print('last')
    # print(vum,v,d,f,t)
    return d,f,t

def main():
    n = int(input())
    rows = []
    for i in range(n):
        rows.append([int(x) for x in input().split()])

    vum = {}
    for v,row in enumerate(rows):
        u,k = row[0],row[1]
        ul = []
        if k > 0:
            for j in row[2:]:
                ul.append(j-1)
        vum.update({v:ul})

    # print(vum)
    d = [-1]*len(vum)
    f = [-1]*len(vum)
    t = 0
    for v in vum:
        d,f,t = dfs(vum,v,d,f,t)
    for i,(j,k) in enumerate(zip(d,f)):
        print(i+1,j,k)

if __name__ == '__main__':
    main()

Python: n=int(input())
adj=[None]
for i in range(n):
    adj_i=list(map(int,input().split()[2:]))
    adj.append(adj_i)
sndf=[None]
for i in range(1,n+1):
    sndf.append([False,i])
path=[]
time=0
def dfs(u):
    global time
    sndf[u][0]=True
    time+=1
    sndf[u].append(time)
    for v in adj[u]:
        if not sndf[v][0]:
            dfs(v)
    time+=1
    sndf[u].append(time)
for i in range(1,n+1):
    if not sndf[i][0]:
        dfs(i)
for x in sndf[1:]:
    print(*x[1:])