Submission #6799178

---

Source Code Expand

n,m=map(int,input().split())
p_list=[list(map(lambda x:int(x)-1,input().split()))[1:] for _ in [0]*n]

p_check=[False for _ in [0]*n]
l_check=[False for _ in [0]*m]
l_list=[[] for _ in [0]*m]

for k,i in enumerate(p_list):
    for j in i:
        l_list[j].append(k)

for i,j in enumerate(l_list):
    if j!=[]:
        q=[i]
        break

l_check[q[0]]=True

while q:
    qq=q.pop()
    p=l_list[qq]
    for pp in p:
        if p_check[pp]==False:
            p_check[pp]=True
            for l in p_list[pp]:
                if l_check[l]==False:
                    l_check[l]=True
                    q.append(l)

print(["NO","YES"][all(p_check)])

Submission Info

Judge Result