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: 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()