Submission #993645

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Source Code Expand

n, m = map(int, raw_input().split())
g = [[] for i in xrange(m)]
L = [None]*n
for i in xrange(n):
    ipt = map(int, raw_input().split())
    k = ipt[0]
    L[i] = ipt[1:]
    for e in L[i]:
        g[e-1].append(i)
parent = range(n)
def root(x):
    if x == parent[x]:
        return x
    parent[x] = root(parent[x])
    return parent[x]
def unite(x, y):
    px = root(x)
    py = root(y)
    if px < py:
        parent[py] = px
    elif px > py:
        parent[px] = py
    return min(px, py)
for e in g:
    for i in xrange(len(e)-1):
        unite(e[i], e[i+1])
print "YES"*(sum(parent) == 0) or "NO"

Submission Info

Judge Result