Технокубок 2021 - Финал
C
Basic Diplomacy
Codeforces
1600
原题
← BD →
翻译中…

Aleksey has $n$ friends. He is also on a vacation right now, so he has $m$ days to play this new viral cooperative game! But since it's cooperative, Aleksey will need one teammate in each of these $m$ days.

翻译中…

On each of these days some friends will be available for playing, and all others will not. On each day Aleksey must choose one of his available friends to offer him playing the game (and they, of course, always agree). However, if any of them happens to be chosen strictly more than $\left\lceil\dfrac{m}{2}\right\rceil$ times, then all other friends are offended. Of course, Aleksey doesn't want to offend anyone.

翻译中…

Help him to choose teammates so that nobody is chosen strictly more than $\left\lceil\dfrac{m}{2}\right\rceil$ times.

翻译中…

Input

翻译中…

Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 10\,000$). Description of the test cases follows.

翻译中…

The first line of each test case contains two integers $n$ and $m$ ($1\leq n, m\leq 100\,000$) standing for the number of friends and the number of days to play, respectively.

翻译中…

The $i$-th of the following $m$ lines contains an integer $k_i$ ($1\leq k_i\leq n$), followed by $k_i$ distinct integers $f_{i1}$, ..., $f_{ik_i}$ ($1\leq f_{ij}\leq n$), separated by spaces — indices of available friends on the day $i$.

翻译中…

It is guaranteed that the sums of $n$ and $m$ over all test cases do not exceed $100\,000$. It's guaranteed that the sum of all $k_i$ over all days of all test cases doesn't exceed $200\,000$.

翻译中…

Output

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Print an answer for each test case. If there is no way to achieve the goal, print "NO".

翻译中…

Otherwise, in the first line print "YES", and in the second line print $m$ space separated integers $c_1$, ..., $c_m$. Each $c_i$ must denote the chosen friend on day $i$ (and therefore must be one of $f_{ij}$).

翻译中…

No value must occur more than $\left\lceil\dfrac{m}{2}\right\rceil$ times. If there is more than one possible answer, print any of them.

翻译中…

样例

Input #1
2
4 6
1 1
2 1 2
3 1 2 3
4 1 2 3 4
2 2 3
1 3
2 2
1 1
1 1
Output #1
YES
1 2 1 1 2 3
NO
InputCopy OutputCopy
题目信息
题号
1482C
时间限制
2 s
内存限制
512 MB
标签
暴力
构造
贪心
模拟

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。