Go: package main

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

//util
var sc = bufio.NewScanner(os.Stdin)

func nextStr() string {
	sc.Scan()
	return sc.Text()
}

func nextInt() int {
	sc.Scan()
	i, e := strconv.Atoi(sc.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func printList(list []int) {
	n := len(list)
	buf := bufio.NewWriter(os.Stdout)
	for _, v := range list[0 : n-1] {
		buf.Write([]byte(fmt.Sprintf("%d ", v)))
	}
	buf.Write([]byte(fmt.Sprintf("%d\n", list[n-1])))
	buf.Flush()
}

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

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

//solve

const MAX = 100
const WHITE = 0
const GRAY = 1
const BLACK = 2

var time, n int

//隣接行列
var M [MAX][MAX]int

//d[i]: 最初にiを訪問した時刻。発見時刻
//f[i]: iの隣接リストを訪問し終えた時刻。完了時刻
var color, d, f [MAX]int

func dfs_visit(u int) {
	color[u] = GRAY
	time++
	d[u] = time
	//隣接を調べる
	for v := 0; v < n; v++ {
		if M[u][v] == 0 {
			continue
		}
		//隣接するvが、未訪問だった場合
		if color[v] == WHITE {
			dfs_visit(v)
		}
	}
	//訪問完了処理
	color[u] = BLACK
	time++
	f[u] = time
	//訪問完了
}

func dfs() {
	//初期化
	for u := 0; u < n; u++ {
		color[u] = WHITE
	}
	time = 0

	//未訪問のuを始点として、深さ優先探索
	for u := 0; u < n; u++ {

		if color[u] == WHITE {
			dfs_visit(u)
		}
	}

	for u := 0; u < n; u++ {
		fmt.Println(u+1, d[u], f[u])
	}
}

func main() {
	sc.Split(bufio.ScanWords)
	n = nextInt()
	for i := 0; i < n; i++ {
		u, k := nextInt(), nextInt()
		M[u-1][u-1] = 0

		//fmt.Println(u, k)
		if k > 0 {
			for j := 0; j < k; j++ {

				v := nextInt()
				M[u-1][v-1] = 1

			}
		}

	}

	dfs()

}

Python: from collections import deque


def conv_list(n):
    adj_matrix = []
    for _ in range(n):
        adj_list = input().split()
        adj_list = list(map(int, adj_list))
        adj_row = [False] * n
        if adj_list[1] > 0:
            for i in adj_list[2:]:
                adj_row[i - 1] = True
        adj_matrix.append(adj_row)
    return adj_matrix


def depth_first_search(adj_matrix, n):
    visited = [None] * n
    count = 1
    searched = [None] * n
    start = 0
    stack = deque()
    stack.append(start)
    visited[start] = 1
    while count <= 2 * n:
        has_edge = adj_matrix[start]
        i = 0
        while i < n:
            if has_edge[i] and visited[i] is None:
                stack.append(i)
                count += 1
                visited[i] = count
                break
            i += 1
        if i < n:
            start = i
        else:
            searched_node = stack.pop()
            count += 1
            searched[searched_node] = count
            if len(stack) > 0:
                start = stack[-1]
            elif count < 2 * n:
                start = visited.index(None)
                stack.append(start)
                count += 1
                visited[start] = count
            else:
                break
    return visited, searched


def main():
    n = int(input())
    adj_matrix = conv_list(n)
    visited, searched = depth_first_search(adj_matrix, n)
    for i in range(n):
        print("{} {} {}".format(i + 1, visited[i], searched[i]))


if __name__ == "__main__":
    main()

Python: import sys
readline = sys.stdin.readline
write = sys.stdout.write

N = int(readline())
G = [None]*(N+1)
for i in range(N):
    u, k, *vs = map(int, readline().split())
    G[u] = vs


begin = [-1]*(N+1)
end = [-1]*(N+1)
lb = iter(range(1, 2*N+1)).__next__
def dfs(v):
    begin[v] = lb()
    for w in G[v]:
        if begin[w] != -1:
            continue
        dfs(w)
    end[v] = lb()


for v in range(1, N+1):
    if begin[v] != -1:
        continue
    dfs(v)
write("\n".join("{} {} {}".format(*args) for args in zip(range(1, N+1), begin[1:], end[1:])))
write("\n")

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 i in range(n):
    print(str(i+1), str(d[i]), str(f[i]), 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: n = int(input())
graph = {}

for i in range(1, n + 1):
    data = input().split()
    graph[i] = [int(i) for i in data[2:]]


class dfs:
    def __init__(self, graph):
        self.g = graph
        self.visited = set()
        self.time = 0
        self.res = {}

    def dfs(self, cur):
        self.visited.add(cur)
        self.time += 1
        start = self.time
        for node in self.g[cur]:
            if node not in self.visited:
                self.dfs(node)
        self.time += 1
        end = self.time
        self.res[cur] = (start, end)


solver = dfs(graph)
for i in range(1, n + 1):
    if i not in solver.visited:
        solver.dfs(i)

for i in range(1, n + 1):
    print(i, solver.res[i][0], solver.res[i][1])

Python: N = int(input())

nodes = [tuple(map(int, input().split(' '))) for _ in range(N)]
d = [-1 for _ in range(N + 1)]
f = [-1 for _ in range(N + 1)]

clock = 0


def dfs(node):
    global clock
    if d[node] == -1:
        clock += 1
        d[node] = clock
    neighbors = sorted(nodes[node - 1][2:])

    for neighbor in neighbors:
        if d[neighbor] == -1:
            dfs(neighbor)

    if f[node] == -1:
        clock += 1
        f[node] = clock


for i in range(1, N + 1):
    dfs(i)
    print(i, d[i], f[i])

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

time, current = 1, 0
stack = []
d[current] = time
while 0 in f:
    if not stack:
        stack.append(0)
    time += 1
    current = stack[-1]
    for i in range(len(mat[current])):
        if mat[current][i] and not d[i]:
            current = i
            d[i] = time
            stack.append(i)
            break
    else:
        f[current] = time
        current = stack.pop()

for l in zip(range(1, n + 1), d, f):
    print(*l)

Python: from collections import defaultdict


def dfs(v, t):
    if start[v] == 0:
        start[v] = t
        t += 1
    else:
        return t

    for nv in graph[v]:
        t = dfs(nv, t)

    end[v] = t
    t += 1

    return t


n = int(input())

graph = defaultdict(list)

for _ in range(n):
    u, k, *v = map(int, input().split())
    for v in v:
        graph[u].append(v)

start = [0] * (n + 1)
end = [0] * (n + 1)


t = 1

for i in range(1, n + 1):
    t = dfs(i, t)

for i in range(1, n + 1):
    print(i, start[i], end[i])

Python: 
d = None
f = None


def dfs(g, cur, time):
    global d, f
    d[cur] = time
    for next in g[cur]:
        if d[next] == 0:
            time = dfs(g, next, time+1)
    f[cur] = time + 1
    return time + 1


def main():
    global d, f
    n = int(input())
    g = [[] for _ in range(n)]
    d = [0 for _ in range(n)]
    f = [0 for _ in range(n)]
    for _ in range(n):
        inp = list(map(int, input().split()))
        m = inp[0] - 1
        k = inp[1]
        for i in range(k):
            g[m].append(inp[i+2] - 1)
    dfs(g, 0, 1)
    for i in range(n):
        print(i, d[i], f[i])


if __name__ == '__main__':
    main()