Go: #include <bits/stdc++.h>
using namespace std;
static const int WHITE = 0;
static const int GRAY  = 1;
static const int BLACK = 2;
static const int N     = 100;

int n, tt;
vector<vector<int>> M(N, vector<int>(N));
vector<int> color(N), d(N), f(N);

void dfs_visit(int u) {
  color[u] = GRAY;
  d[u]     = ++tt;
  for (int v = 0; v < n; v++) {
    if (M[u][v] == 0) continue;
    if (color[v] == WHITE) { dfs_visit(v); }
  }
  color[u] = BLACK;
  f[u]     = ++tt;
}

void dfs() {
  tt = 0;

  for (int u = 0; u < n; u++) {
    if (color[u] == WHITE) dfs_visit(u);
  }
  for (int u = 0; u < n; u++) {
    printf("%d %d %d\n", u + 1, d[u], f[u]);
  }
}

int main() {
  int u, v, k;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> u >> k;
    u--;
    for (int j = 0; j < k; j++) {
      cin >> v;
      v--;
      M[u][v] = 1;
    }
  }

  dfs();
}

Python: def dfs(v, k):
    if ans[v][1] == 0:
        ans[v][1] = k
    else:
        return k - 1
    for i in d[v]:
        k = dfs(i, k + 1)
    k += 1
    if ans[v][2] == 0:
        ans[v][2] = k
    return k


G = int(input())
vlst = [list(map(int, input().split())) for _ in range(G)]
d = [[] for _ in range(G)]
for i in range(G):
    for j in range(vlst[i][1]):
        d[i].append(vlst[i][2 + j] - 1)
ans = [[_, 0, 0] for _ in range(G)]
k = 1
for i in range(G):
    k = dfs(i, k) + 1
for i in ans:
    print(i[0] + 1, i[1], i[2])

Python: from collections import defaultdict


n = int(input())
rel = defaultdict(set)

times = {}
for _ in range(n):
    rl = list(map(int, input().split()))
    p, ts = rl[0], rl[2:]
    rel[p] = sorted(ts, reverse=True)
    times[p] = {'first': 0, 'last': 0}

t = 0

for f in range(1, len(rel)+1):
    if times[f]['last']:
        continue
    stack = [f]
    while stack:
        u = stack[-1]
        if times[u]['first']:
            if not times[u]['last']:
                t += 1
                times[u]['last'] = t
            stack.pop()
            continue
        t += 1
        times[u]['first'] = t
        for v in rel[u]:
            if not times[v]['first']:
                stack.append(v)

for k in sorted(times):
    print(k, times[k]['first'], times[k]['last'])

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