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: def DFS(G):
    ans = [0] + [[0,0,0] for _ in range(len(G))]
    def main(G,i):
        ans[0] += 1
        ans[i] = [i, ans[0], ans[0]]
        for j in sorted(G[i-1][2:]):
            if ans[j][0] == 0: main(G,j)
        ans[0] += 1
        ans[i][2] = ans[0]
    for u in G:
        if ans[u[0]][0] == 0: main(G,u[0])
    return ans[1:]


if __name__=='__main__':
    n = int(input())
    G = [list(map(int,input().split())) for _ in range(n)]
    for out in DFS(G): print(*out)

Python: n = int(input())
g = []
for i in range(n):
    a = list(map(int,input().split()))
    g.append(a[2:])
d = [0]*n
f = [0]*n
global t
t = 1
d[0] = 1
x = 1
def find(x):
    global t
    if len(g[x-1]) == 0:
        f[x-1] = t
    for i in g[x-1]:
        if d[i-1] == 0:
            t += 1
            d[i-1] = t
            find(i)
    t += 1
    f[x-1] = t

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

Python: n = int(input())
A = [[False for _ in range(n)] for _ in range(n)]
for _ in range(n):
    tmp = list(map(int, input().split()))
    for i in range(tmp[1]):
        A[tmp[0]-1][tmp[i+2]-1] = True

WHITE = 0
GRAY = 1
BLACK = 2
color = [WHITE for _ in range(n)]
d = [0 for _ in range(n)]
f = [0 for _ in range(n)]
time = 1

def dfs(u):
    global dfs_color, d, f, time
    color[u] = GRAY
    d[u] += time
    time += 1
    for v in range(n):
        if A[u][v]:
            if color[v] == WHITE:
                dfs(v)
        else:
            continue
    color[u] = BLACK
    f[u] = time
    time += 1 

for u in range(n):
    if color[u] == WHITE:
        dfs(u)

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

Python: n = int(input())
graph = {}
for _ in range(n):
  i = list(map(int,input().split()))
  graph[i[0]] = i[2:]

first = {i:0 for i in range(1,n+1)}
last = {i:0 for i in range(1,n+1)}
seen = set()
time = 1

def dfs(v):
  global time
  seen.add(v)
  first[v] = time
  time += 1
  for nxt in graph[v]:
    if nxt in seen:
      continue
    dfs(nxt)
  last[v] = time
  time += 1

for i in range(1,n+1):
  if i not in seen:
    dfs(i)
  
for i in range(1,n+1):
  print(i, first[i], last[i])

Python: import sys

def debug(x, table):
    for name, val in table.items():
        if x is val:
            print('DEBUG:{} -> {}'.format(name, val), file=sys.stderr)
            return None

time = 0

def dfs(u, adj, d, f, sumi):
    global time
    time += 1
    d[u] = time

    for v in adj[u]:
        if v not in sumi:
            dfs(v, adj, d, f, sumi)
        sumi.add(v)

    time += 1

    f[u] = time


def solve():
    n = int(input())
    adj = [None] * n

    for i in range(n):
        u, k, *vs = [int(j) - 1 for j in input().split()]
        # debug(vs, locals())
        adj[u] = vs

    # debug(adj, locals())
    
    d = [0] * n
    f = [0] * n
    sumi = {0}

    dfs(0, adj, d, f, sumi)

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

    pass

if __name__ == '__main__':
    solve()

Python: #!/usr/bin/env python
# -*- coding: utf-8 -*-

import sys

WHITE, GRAY, BLACK = 0, 1, 2


def generate_adj(v_info):
    for v_detail in v_info:
        v_adj_list = v_detail[2:]
        assert len(v_adj_list) == int(v_detail[1])
        for each in v_adj_list:
            init_adj_matrix[int(v_detail[0]) - 1][int(each) - 1] = 1
    return init_adj_matrix


def graph_dfs(start_node_index):
    # init the first node
    v_index = int(start_node_index)
    vertex_visit_stack.append(v_index)
    vertex_color_list[v_index] = GRAY
    time = 1
    vertex_d_time[v_index] += time
    # init end
    while len(vertex_visit_stack) > 1:
        current_vertex = vertex_visit_stack[-1]
        try:
            next_vertex = adj_matrix[current_vertex - 1].index(1) + 1
        except ValueError:
            # print('err')
            vertex_visit_stack.pop()
            vertex_color_list[current_vertex] = BLACK
            time += 1
            vertex_f_time[current_vertex] += time
        else:
            if vertex_color_list[next_vertex] == WHITE:
                # print('w2g', current_vertex, next_vertex, vertex_color_list[next_vertex])
                vertex_color_list[next_vertex] = GRAY
                time += 1
                vertex_d_time[next_vertex] += time
                vertex_visit_stack.append(next_vertex)
                # node A to B only visit once
                adj_matrix[current_vertex - 1][next_vertex - 1] = 0
            else:
                time += 1
                vertex_f_time[current_vertex] += time
                vertex_visit_stack.pop()
    return None


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    vertex_num = int(_input[0])
    vertex_info = list(map(lambda x: x.split(), _input[1:]))
    init_adj_matrix = [[0] * vertex_num for _ in range(vertex_num)]
    # assert len(vertex_info) == vertex_num

    vertex_visit_stack = [-1]
    vertex_color_list = [WHITE] * (vertex_num + 1)
    vertex_d_time, vertex_f_time = [0] * (vertex_num + 1), [0] * (vertex_num + 1)
    adj_matrix = generate_adj(vertex_info)

    graph_dfs(start_node_index=1)
    for i in range(vertex_num):
        print(i + 1, vertex_d_time[i + 1], vertex_f_time[i + 1])

Python: n = int(input())

graph = []
for _ in range(n):
    tmp = list(map(int, input().split()))
    if tmp[1] == 0:
        graph.append([])
    else:
        graph.append(tmp[2:])
#print(graph)

seen = [0]*n
to_do = []
in_list = [0]*n
out_list = [0]*n
count = 0

def dfs(v):
    #print(v)
    global count
    if seen[v] == 0:
        seen[v] = 1
        count += 1
        in_list[v] = count
        to_do = graph[v]
        #print(in_list)
        #print(to_do)
        if len(to_do) > 0:
            for i in to_do:
                dfs(i-1)
        count += 1
        out_list[v] = count
        #print(out_list)
while True:
    if 0 in seen:
        k = seen.index(0)
        dfs(k)
    else:
        break

for i in range(n):
    print("{} {} {}".format(i+1,in_list[i],out_list[i]))

Python: # http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_11_B&lang=ja
import sys
input = sys.stdin.readline

N = int(input())
G = [[a-1 for a in list(map(int, input().split()))[2:]] for _ in [0]*N]
visited = [0]*N
history = [[] for _ in [0]*N]

k = 0


def dfs(v=0, p=-1):
    global k
    visited[v] = 1
    k += 1
    history[v].append(k)

    for u in G[v]:
        if u == p or visited[u]:
            continue
        dfs(u, v)

    k += 1
    history[v].append(k)


for i in range(N):
    if not visited[i]:
        dfs(i)

for i, h in enumerate(history):
    print(i+1, *h)