Go: package main

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

/***************************************************************
stackによる深さ優先探索を実装する。
***************************************************************/

const (
	N     = 100
	WHITE = 0
	GRAY  = 1
	BLACK = 2
)

var (
	n            int
	Adj          [N][N]int
	statusColor  [N]int
	discoverTime [N]int
	finishTime   [N]int
	clock        int
	nt           [N]int
)

/***************************************************************
Stackの定義:
- field
	container: ノードの格納されたスライス
	sp: スタックポインタ
- method
	size(): スタックに積まれているノードの個数を返す
	top(): スタックの一番上に積まれているノードを返す
	isEmpty(): スタックが空かどうかを返す
	pop(): スタックの要素をポップし削除する
	push(): スタックに要素を積む
***************************************************************/

type Stack struct {
	container []int
	sp        int
}

func (s *Stack) size() int {
	return len(s.container)
}

func (s *Stack) top() int {
	return s.container[s.sp]
}

func (s *Stack) isEmpty() bool {
	return s.sp == 0
}

func (s *Stack) pop() int {
	_pop := func() {
		s.container = s.container[:len(s.container)-1]
	}
	defer _pop()
	if s.isEmpty() {
		panic("There is no elements in stack!")
	}
	s.sp--
	return s.container[s.sp]
}

func (s *Stack) push(n int) {
	s.sp++
	s.container[s.sp] = n
}

func next(u int) int {
	for v := nt[u]; v < n; v++ {
		nt[u] = v + 1
		if Adj[u][v] == 1 {
			return v
		}
	}
	return -1
}

func _DFS(target int) {
	for i := 0; i < n; i++ {
		nt[i] = 0
	}
	stack := new(Stack)
	stack.container = make([]int, N+1)
	stack.push(target)
	statusColor[target] = GRAY
	clock++
	discoverTime[target] = clock
	for !stack.isEmpty() {
		u := stack.top()
		v := next(u)
		if v != -1 {
			if statusColor[v] == WHITE {
				statusColor[v] = GRAY
				clock++
				discoverTime[v] = clock
				stack.push(v)
			}
		} else {
			stack.pop()
			statusColor[u] = BLACK
			clock++
			finishTime[u] = clock
		}
	}
}

func DFS() {
	for i := 0; i < n; i++ {
		statusColor[i] = WHITE
		nt[i] = 0
	}
	clock = 0
	for i := 0; i < n; i++ {
		if statusColor[i] == WHITE {
			_DFS(i)
		}
	}
	for i := 0; i < n; i++ {
		fmt.Printf("%d %d %d\n", i+1, discoverTime[i], finishTime[i])
	}
}

func main() {
	scanner := bufio.NewScanner(os.Stdin)
	scanner.Split(bufio.ScanWords)
	scanner.Scan()
	n, _ = strconv.Atoi(scanner.Text())
	for i := 0; i < n; i++ {
		for j := 0; j < n; j++ {
			Adj[i][j] = 0
		}
	}
	for i := 0; i < n; i++ {
		scanner.Scan()
		u, _ := strconv.Atoi(scanner.Text())
		scanner.Scan()
		k, _ := strconv.Atoi(scanner.Text())
		u--
		for j := 0; j < k; j++ {
			scanner.Scan()
			v, _ := strconv.Atoi(scanner.Text())
			v--
			Adj[u][v] = 1
		}
	}

	DFS()
}

Python: import sys
sys.setrecursionlimit(10000000)
MOD = 10 ** 9 + 7
INF = 10 ** 15

G = [[] for _ in range(105)]
begin = [-1] * 105
end = [-1] * 105

t = 1
def dfs(v):
    global t
    begin[v] = t
    t += 1
    for e in G[v]:
        if begin[e] < 0:
            dfs(e)
    end[v] = t
    t += 1

def main():
    N = int(input())
    for i in range(N):
        A = list(map(int,input().split()))
        for a in A[2:]:
            G[i].append(a - 1)
    
    for i in range(N):
        if begin[i] < 0:
            dfs(i)
    for i in range(N):
        print(i + 1,begin[i],end[i])
if __name__ == '__main__':
    main()

Python: 
#kadai11b Depth First Search

n=int(input())
t=1
a=[[0 for i in range(n)]for j in range(n)]
t1=[0 for i in range(n)]
t2=[0 for i in range(n)]
s=[]
c=[]
s.append(0)
t1[0]=t
t+=1
for i in range(n):
    p=[int(x) for x in input().split()]
    for j in range(n):
        if j+1 in p[2:]:
            a[i][j]=1

i=0
while len(c)!=n:
    if 1 not in a[i][0:]:
        if i not in c:
            t2[i]=t
            t+=1
            c.append(i)
            del s[-1]
            if len(s)>0:
                i=s[-1]
    for j in range(n):
        if a[i][j]==1:
            a[i][j]=0
            if j not in c:
                s.append(j)
                i=j
                t1[i]=t
                t+=1
            break

for i in range(n):
    print(i+1,t1[i],t2[i])

"""実行結果
6
1 2 2 3
2 2 3 4
3 1 5
4 1 6
5 1 6
6 0
1 1 12
2 2 11
3 3 8
4 9 10
5 4 7
6 5 6
"""

Python: import sys
n = int(input())
input_line = [[int(i) for i in str.split()] for str in sys.stdin.read().splitlines()]
for i in range(n):
    input_line[i] = [] if len(input_line[i]) == 2 else input_line[i][2:]
detect_time = [0] * n
finish_time = [0] * n
is_visit = [False] * n
stack = []
time = 0

while(time < n*2):
    time += 1
    id = is_visit.index(False) + 1
    stack.append(id)
    is_visit[id-1] = True
    detect_time[id-1] = time
    while(len(stack) != 0):
        id = stack[-1]
        if len(input_line[id-1]) == 0:
            time += 1
            finish_time[stack.pop()-1] = time
        else:
            detect_id = input_line[id-1].pop(0)
            if is_visit[detect_id-1]:
                continue
            stack.append(detect_id)
            time += 1
            detect_time[detect_id-1] = time
            is_visit[detect_id-1] = True


for id in range(n):
    print('{0} {1} {2}'.format(id+1, detect_time[id], finish_time[id]))

Python: 
def DFS(n = 1, i = 0, time = 1):
    for j in range(n):
        if A[i][j] == 1 and d[j] == 0:
            time = time + 1
            d[j] = time
            time = DFS(n, j, time)
    time = time + 1
    f[i] = time
    return time

n = int(raw_input())
A = [0] * n
for i in range(n):
    A[i] = [0] * n

for i in range(n):
    value = map(int, raw_input().split())
    u = value[0] - 1
    k = value[1]
    nodes = value[2:]
    for j in range(k):
        v = nodes[j] - 1
        A[u][v] = 1

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

time = 0
for i in range(n):
    if d[i] == 0:
        time = time + 1
        d[i] = time
        time = DFS(n, i, time)

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

Python: WHITE = 0
GRAY = 1
BLACK = 2

n = int(input())

M = [[0] * n for i in range(n)]

d = [0] * (n)
f = [0] * (n)
color = [WHITE] * (n)


time = 0

def dfs_visit(u):
    global time
    time += 1
    color[u] = GRAY
    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():
    for u in range(n):
        if color[u] == WHITE:
            dfs_visit(u)

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


if __name__ == "__main__":
    for i in range(n):
        arr = list(map(int, input().split()))
        for v in (arr[2:]):
            M[arr[0]-1][v-1] = 1

    dfs()

Python: #coding:utf-8
from copy import deepcopy

n = int(input())
c = ["white" for i in range(n)]
d = [0 for i in range(n)]
f = [0 for i in range(n)]
S = []
class DFS:
    def __init__(self, key, color="white",nex=None):
        self.color = color
        self.nex = nex
        self.key = key

objList = [DFS(i+1) for i in range(n)]
for i in range(n):
    data = list(map(int,input().split()))
    times = data[1]
    obj = objList[i]
    for j in range(times):
        index = data[2+j] - 1
        nextobj = DFS(index+1)
        obj.nex = nextobj
        obj = obj.nex


time = 1
def check(first,time):
    obj = objList[first]
    c[first] = "gray"
    d[first] = time
    f[first] = time
    S.append(first+1)
    
    while S != []:
        index = S[-1] - 1
        u = objList[index]
        v = u.nex
    
        if v != None:
            objList[index] = v
            if c[v.key - 1] == "white":
                index = v.key - 1
                v = objList[index]
                c[v.key-1] = "gray"
                time += 1
                d[index] = time
                S.append(v.key)

           
                
        else:
            S.pop()
            c[u.key-1] = "black"
            time += 1
            f[index] = time
    return time


for i in range(n):
    if f[i] == 0:
        time = check(i,time) + 1
        

k = 1
for i,j in zip(d,f):
    print(k,i,j)
    k += 1