7171: ABC272 —— B - Everyone is Friends
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Description
There are $N$ people numbered $1,2,\ldots,N$.
$M$ parties were held. $k_i$ people attended the i-th ($1\leq i \leq M$) party, and they were People $x_{i,1},x_{i,2},\ldots,x_{i,k_i}$.
Determine if every two people attended the same party at least once.
$M$ parties were held. $k_i$ people attended the i-th ($1\leq i \leq M$) party, and they were People $x_{i,1},x_{i,2},\ldots,x_{i,k_i}$.
Determine if every two people attended the same party at least once.
Input
The input is given from Standard Input in the following format:
$N\ M$
$k_1\ x_{1,1}\ x_{1,2}\ \ldots\ x_{1,k_1}$
$\vdots$
$k_M\ x_{M,1}\ x_{M,2}\ \ldots\ x_{M,k_M}$
$N\ M$
$k_1\ x_{1,1}\ x_{1,2}\ \ldots\ x_{1,k_1}$
$\vdots$
$k_M\ x_{M,1}\ x_{M,2}\ \ldots\ x_{M,k_M}$
Output
Print Yes if every two people attended the same party at least once; print No otherwise.
Constraints
$2≤N≤100$
$1\leq M \leq 100$
$2\leq k_i \leq N$
$1\leq x_{i,1}<x_{i,2}<\ldots < x_{i,k_i}\leq N$
All values in the input are integers.
$1\leq M \leq 100$
$2\leq k_i \leq N$
$1\leq x_{i,1}<x_{i,2}<\ldots < x_{i,k_i}\leq N$
All values in the input are integers.
Sample 1 Input
3 3
2 1 2
2 2 3
2 1 3
Sample 1 Output
Yes
Both Person 1 and Person 2 attended the 1-st party.
Both Person 2 and Person 3 attended the 2-nd party.
Both Person 1 and Person 3 attended the 3-rd party.
Therefore, every two people attended the same party at least once, so the answer is Yes.
Sample 2 Input
4 2
3 1 2 4
3 2 3 4
Sample 2 Output
No
Person 1 and Person 3 did not attend the same party, so the answer is No.