Go: package main

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

func main() {
	sc := bufio.NewScanner(os.Stdin)
	sc.Split(bufio.ScanWords)

	nVerts := scanInt(sc)
	graph := make([][]int, nVerts+1)

	for i := 0; i < nVerts; i++ {
		u := scanInt(sc)
		nDegrees := scanInt(sc)

		graph[u] = make([]int, nDegrees)
		for d := 0; d < nDegrees; d++ {
			graph[u][d] = scanInt(sc)
		}
	}

	starts := make([]int, nVerts+1)
	ends := make([]int, nVerts+1)
	time := 1

	var dfs func(u int)
	dfs = func(u int) {
		if starts[u] > 0 {
			return
		}

		starts[u] = time
		time += 1

		for _, v := range graph[u] {
			dfs(v)
		}

		ends[u] = time
		time += 1
	}

	for i := 1; i <= nVerts; i++ {
		dfs(i)
	}

	w := bufio.NewWriter(os.Stdout)
	for i := 1; i <= nVerts; i++ {
		fmt.Fprintf(w, "%d %d %d\n", i, starts[i], ends[i])
	}
	w.Flush()
}

func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	v, _ := strconv.Atoi(sc.Text())
	return v
}

Python: def dfs(adj, s, d, f, now):
    now += 1
    d[s] = now
    for t in adj[s]:
        if f[t] < 0:
            d, f, now = dfs(adj, t, d, f, now)
    now += 1
    f[s] = now
    return d, f, now


n = int(input())
adj = [[] for _ in range(n)]
for _ in range(n):
    s = [int(x) for x in input().split()]
    u = s[0]
    for v in s[2:]:
        adj[u - 1].append(v - 1)
    adj[u - 1].sort()

d = [1 for _ in range(n)]
f = [-1 for _ in range(n)]
d, f, _ = dfs(adj, 0, d, f, 0)

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

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

"""
input:
6
1 2 2 3
2 2 3 4
3 1 5
4 1 6
5 1 6
6 0

output:
1 1 12
2 2 11
3 3 8
4 9 10
5 4 7
6 5 6
"""
import sys
from collections import deque

UNVISITED, VISITED_IN_STACK, POPPED_OUT = 0, 1, 2


def generate_adj_matrix(v_info):
    for v_detail in v_info:
        v_index, adj_num, *adj_list = map(int, v_detail)
        # assert len(adj_list) == adj_num
        init_adj_table[v_index].extend(sorted(adj_list))
    return init_adj_table


def graph_dfs(v_init):
    global time

    # init the first node of overall graph iterations(times >= 1)
    stack.append(v_init)
    color[v_init] = VISITED_IN_STACK
    d_time[v_init] += time
    # init end

    while len(stack) > 1:
        current = stack[-1]
        v_table = adj_table[current]
        adj = v_table.popleft() if v_table else None

        if adj:
            if color[adj] is UNVISITED:
                color[adj] = VISITED_IN_STACK
                time += 1
                d_time[adj] += time
                stack.append(adj)
        else:
            stack.pop()
            color[current] = POPPED_OUT
            time += 1
            f_time[current] += time

    return None


def dfs_start():
    global time
    for i in range(vertices_num):
        if color[i + 1] == UNVISITED:
            # print('round: ', i + 1)
            graph_dfs(i + 1)
            time += 1


if __name__ == '__main__':
    _input = sys.stdin.readlines()
    vertices_num = int(_input[0])
    vertices_info = map(lambda x: x.split(), _input[1:])
    init_adj_table = tuple(deque() for _ in range(vertices_num + 1))
    # assert len(vertex_info) == vertex_num

    # config length = (vertex_num + 1)
    stack = [-1]
    color = [UNVISITED] * (vertices_num + 1)
    d_time, f_time = ([0] * (vertices_num + 1) for _ in range(2))

    adj_table = generate_adj_matrix(vertices_info)
    # timing start from 1
    time = 1
    dfs_start()
    for k, v in enumerate(zip(d_time[1:], f_time[1:]), 1):
        print(k, *v)

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

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

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

Python: n=0
t=1
def adjacent_matrix():
    global n
    n=int(input())
    v=[]
    array=[]
    for i in range(n):
        zero=[0 for i in range(n)]
        a=list(map(int,input().split()))
        a=a[2:]
        for j in a:
            zero[j-1]=1
        array.append(zero)
    return array
def dfs(array,i,d,f):
    global t
    if i == n:
        return
    else:
        if(d[i] == 0):
            d[i] = t
            t += 1
            for (j,x) in enumerate(array[i]):
                if x == 1:
                    dfs(array,j,d,f)
            f[i] = t
            t += 1
    return 


def main():
    array=adjacent_matrix()
    d=[0 for i in range(n)]
    f=[0 for i in range(n)]
    for i in range(n):
        dfs(array,i,d,f)
    for i in range(n):
        print("{} {} {}".format(i+1,d[i],f[i]))

if __name__ == "__main__":
    main()

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

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

Python: n=int(input())
g=[]
for i in range(n):
    u,k,*varray= map(int,input().split())
    g.append(varray)

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

def dfs(src):
    global time
    d[src]= time
    time+=1
    for i in g[src]:
        if d[i-1]== -1:
            dfs(i-1)
    f[src]= time
    time+=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: N = int(input())
adj_list = [ [] for _ in range(N+1) ]
for _ in range(N):
  lst = list(map(int,input().split()))
  node = lst[0]
  if lst[1] != 0:
    adj_list[node] = lst[2:]


visited = [False] * (N+1)
arrived = [-1] * (N+1)
left = [-1] * (N+1)

time = 0
def dfs(node):
  global time

  arrived[node] = time
  visited[node] = True

  for nei in adj_list[node]:
    if not visited[nei]:
      time += 1
      dfs(nei)
  else:
    time += 1
    left[node] = time

for i in range(1, N+1):
  if not visited[i]:
    time += 1
    dfs(i)

for i in range(1, N+1):
  print(i, arrived[i], left[i])

Python: # coding: utf-8
def depth(i, adj, Dep, Arr, times):
    if Dep[i-1]:
        return times
    Dep[i-1]=times
    times+=1
    # t=[depth(j, adj, Dep, f, times) j in adj[i-1]]
    for j in adj[i-1]:
        times=depth(j, adj, Dep, Arr, times)
    Arr[i - 1]=times
    times+=1
    return times


n=int(input())
adj=[list(map(int, input().split()))[2:] for i in range(n)]

d,f=[0]*n,[0]*n

t=1

dlist=[i for i in range(n) if d[i]==0]

for i in dlist:
    t = depth(i + 1, adj, d, f, t)

for i, df in enumerate(zip(d, f)):
    print(i + 1, *df)

Python: def main():

    inf = 1000000007
    n = int(input())
    e = [[] for _ in range(n)]
    d = [inf]*n
    f = [inf]*n
    step = 1

    def dfs(v):
        nonlocal step
        d[v] = step
        step+=1
        for u in e[v]:
            if d[u] == inf:dfs(u)
        f[v] = step
        step +=1

    e = [[] for _ in range(n)]
    for i in range(n):
        m = list(map(int,input().split()))
        for j in range(2,len(m)):
            e[m[0]-1].append(m[j]-1)
    for i in range(n):
        if d[i]==inf:dfs(i)
    for i in range(n):
        print (i+1,d[i],f[i])

if __name__ == '__main__':
    main()