Submission #11232545

---

Source Code Expand

from scipy.sparse.csgraph import connected_components
from scipy.sparse import csr_matrix

n, m = map(int, input().split())
row = []
col = []
for i in range(n):
    k, *l = map(int, input().split())
    row += [i] * k
    col += [e + n - 1 for e in l]

cost = [1] * len(row)

graph = csr_matrix((cost, (row, col)), shape=(n + m, n + m))
_, labels = connected_components(graph)

bl = (labels[:n] == labels[0]).all()
print("YES" if bl else "NO")

Submission Info

Judge Result