Submission #992452

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Source Code Expand

# coding: utf-8

import collections
import sys
sys.setrecursionlimit(100000)

def dfs(i):
    if visited[i] == 1:
        return
    visited[i] = 1
    for j in speakers[i]:
        if used_lang[j] == 1:
            continue
        used_lang[j] = 1
        for k in langs[j]:
            dfs(k)


N, M = map(int, input().split())

langs = collections.defaultdict(list)
speakers = [[] for _ in range(N)]

for i in range(N):
    ls = list(map(int, input().split()))
    for j in range(1, ls[0] + 1):
        langs[ls[j]-1].append(i)
        speakers[i].append(ls[j]-1)

visited = [0] * N
used_lang = [0] * M
dfs(0)

if 0 not in visited:
    print("YES")
else:
    print("NO")

Submission Info

Judge Result