Go: package main

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

// repr state of visited node
// WHITE yet visit
// GEAY  visiting
// BLACK visited
const (
	WHITE int = iota
	GRAY
	BLACK
)

type dfsGraph struct {
	g      [][]int
	colors []int
	stime  []int // Start time of visiting node
	ftime  []int // Finish time of visiting node
}

var time int

func makeAdjList() [][]int {
	var n int
	fmt.Scanf("%d", &n)

	adj := make([][]int, n)
	for i := 0; i < n; i++ {
		adj[i] = make([]int, n)
	}

	sc := bufio.NewScanner(os.Stdin)
	for i := 0; i < n; i++ {
		sc.Scan()
		nodeInfo := strings.Split(sc.Text(), " ")
		outDegree, _ := strconv.Atoi(nodeInfo[1])

		if outDegree > 0 {
			for k := 0; k < outDegree; k++ {
				j, _ := strconv.Atoi(nodeInfo[k+2])
				j-- // convert 1 based to 0 based
				adj[i][j] = 1
			}
		}
	}

	return adj
}

func (dg dfsGraph) dfsVisit(u int) {
	// 頂点uを訪問中に設定
	dg.colors[u] = GRAY
	time++
	dg.stime[u] = time

	// uの隣接nodeを訪問
	for v := 0; v < len(dg.g); v++ {
		if dg.g[u][v] == 0 {
			continue // 辺がなければスキップ
		}

		// vが未訪問なら訪問
		if dg.colors[v] == WHITE {
			dg.dfsVisit(v)
		}
	}

	// 頂点uを訪問済みに設定
	dg.colors[u] = BLACK
	time++
	dg.ftime[u] = time
}

func (dg dfsGraph) dfs() {
	for i := 0; i < len(dg.g); i++ {
		if dg.colors[i] == WHITE {
			dg.dfsVisit(i)
		}
	}
}

func (dg dfsGraph) printDfsTime() {
	for i := 0; i < len(dg.g); i++ {
		fmt.Printf("%d %d %d\n", i+1, dg.stime[i], dg.ftime[i])
	}
}

func main() {
	adj := makeAdjList()
	colors := make([]int, len(adj))
	stime := make([]int, len(adj))
	ftime := make([]int, len(adj))
	graph := dfsGraph{adj, colors, stime, ftime}
	graph.dfs()
	graph.printDfsTime()
}

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
    sumi.add(u)
    time += 1
    d[u] = time

    for v in adj[u]:
        if v not in sumi:
            dfs(v, adj, d, f, sumi)
            
    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}
    mitan = set(range(1, n))

    dfs(0, adj, d, f, sumi)
    mitan -= sumi
    # debug(mitan, locals())

    
    while mitan:
        u = min(mitan)
        dfs(u, adj, d, f, sumi)
        mitan -= sumi
        # debug(mitan, locals())
        

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

    pass

if __name__ == '__main__':
    solve()

Python: n = int(input())
graph = [[0 for i in range(n)] for j in range(n)]
d = [0] * n
f = [0] * n
g = [0] * n

time = 0

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

def search(i):
    global time
    time = time + 1
    d[i] = time
    g[i] = 1
    for j in range(i, n):
        if (graph[i][j] == 1) & (g[j] == 0):
            search(j)
    time = time + 1
    f[i] = time


search(0)
[print(i+1, d[i], f[i]) for i in range(n)]

Python: def readinput():
    n=int(input())
    nList=[]
    for _ in range(n+1):
        nList.append([])
    for _ in range(n):
        l=list(map(int,input().split()))
        nList[l[0]]=l[2:]
    return n,nList

WHITE=0
GRAY=1
BLACK=2
color=[]
d=[]
f=[]
_time=0

def dfs(u,nList):
    global color
    global d
    global f
    global _time

    S=[]

    if(color[u]==WHITE):
        S.append(u)
        color[u]=GRAY
        _time+=1
        d[u]=_time

    while(len(S)>0):
        u=S[-1]
        t=next(u,nList)
        if(t!=-1):
            if(color[t]==WHITE):
                S.append(t)
                color[t]=GRAY
                _time+=1
                d[t]=_time
        else:
            S.pop()
            color[u]=BLACK
            _time+=1
            f[u]=_time

def next(u,nList):
    global color
    for t in nList[u]:
        if color[t]==WHITE:
            return t
    else:
        return -1

def main(n,nList):
    global color
    global d
    global f

    color=[WHITE]*(n+1)
    d=[0]*(n+1)
    f=[0]*(n+1)

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

if __name__=='__main__':
    n,nList=readinput()
    main(n,nList)

Python: n = int(input())
graph = {}
ans = []
np = set(range(1,n+1))
for i in range(n):
    t = list(map(int, input().split()))
    v = t[0]
    k = t[1]
    graph[v] = [t[i+2] for i in range(k)]
    np=np - set(graph[v])
    ans.append([v,None,None])

class Time:
    def __init__(self):
        self.time = 0
    def getTime(self):
        self.time += 1
        return self.time

t = Time()

visited = set()
def dfs(graph, target):
    visited.add(target)
    # ???????????????????¨????
    if ans[target - 1][1] is None:
        ans[target - 1][1] = t.getTime()
    if graph[target] == []:
        if ans[target - 1][2] is None:
            ans[target - 1][2] = t.getTime()        
        return
    for v in sorted(graph[target]):
        # # ???????????????????¨????
        if v not in visited:        
            if ans[v - 1][1] is None:
                ans[v - 1][1] = t.getTime()        
            visited.add(target)
            dfs(graph,v)
    if ans[target - 1][2] is None:
        ans[target - 1][2] = t.getTime()

for v in np:
    dfs(graph,v)
for row in ans:
    print(*row)

Python: # -*- coding: utf-8 -*-
import sys
sys.setrecursionlimit(100000)
N = int(input())
adj = [[0]*N for _ in range(N)]
searched = {n: 0 for n in range(N)}
edge = {}

for n in range(N):
    inp = list(map(int, input().split()))
    edge[n] = inp[1]
    for i in inp[2:]:
        adj[inp[0]-1][i-1] = 1

time = 1
stack = []
unsearch = set(range(N))
uncomplete = set(range(N))
result = {n:{"found": 0, "finish": 0} for n in range(N)}

def DFS(i):
    global time
    global unsearch
    
    itr = sorted(unsearch)
    
    for j in itr:
        if adj[i][j] == 1 and j in unsearch:
            result[j]["found"] = time
            time += 1
            unsearch.remove(j)
            DFS(j)
    result[i]["finish"] = time
    time += 1
    
while len(unsearch):
    i = min(unsearch)
    unsearch.remove(i)
    result[i]["found"] = time
    time += 1
    DFS(i)

for n in range(N):
    print("{} {} {}".format(n+1, result[n]["found"], result[n]["finish"]))

Python: # coding: utf-8

visited = [False]*101
discovery_time = [0]*101
finish_time = [0]*101
A = [[] for _ in range(101)]
time = 0

def dfs(n):
    global time
    if visited[n] == True:
        return
    time += 1
    discovery_time[n] = time
    visited[n] = True
    for i in A[n]:
        dfs(i)
    time += 1
    finish_time[n] = time

n = int(input().rstrip())
for i in range(n):
    line = [int(j) for j in input().rstrip().split()]
    A[i+1].extend(line[2:])

for i in range(n):
    dfs(i+1)
    
for i in range(n):
    print(str(i+1)+ " "+ str(discovery_time[i+1])+" "+str(finish_time[i+1]))

Python: #coding: utf-8

n = int(input())
color = ["white" for i in range(n)]
d = [[] for i in range(n)]
global t
t = 0
M = [[False for i in range(n)] for j in range(n)]
for i in range(n):
    data = list(map(int,input().split()))
    u = data[0]
    k = data[1]
    if i == 0:
        start = u
    for v in data[2:2+k]:
        M[u-1][v-1] = True


def search(u,t):
    t += 1
    color[u-1] = "gray"
    d[u-1].append(t)
    for v in range(n):
        if M[u-1][v-1] and color[v-1] == "white":
            t = search(v,t)
    color[u-1] = "black"
    t += 1
    d[u-1].append(t)
    return t

t = search(start, t)
for i in range(n):
    if color[i-1] == "white":
        t += 1
        t = search(i, t)

for i in range(n):
    print(i+1, d[i][0], d[i][1])