Submission #69492211

---

Source Code Expand

import sys,random,bisect
from collections import deque,defaultdict
from heapq import heapify,heappop,heappush
from itertools import permutations
from math import gcd,log

input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())

N = int(input())
activate = [[] for v in range(N)]
done = [0] * N
deq = deque()
for i in range(N):
    a,b = mi()
    if (a,b) == (0,0):
        done[i] = 1
        deq.append(i)
    else:
        activate[a-1].append(i)
        activate[b-1].append(i)

while deq:
    v = deq.popleft()
    for nv in activate[v]:
        if not done[nv]:
            deq.append(nv)
            done[nv] = 1

print(sum(done))

Submission Info

Judge Result