As we are currently experiencing an overwhelming number of web requests for fetching user submissions, we have temporarily disabled the full submissions list. You must now be logged in to view submissions.
给出一个简单无向图，判断是否存在两个长度相同的简单环。
第一行两个正整数 $n$, $m$ 表示点数和边数。
接下来 $m$ 行每行两个正整数描述一条边。
若存在，输出 Yes；否则，输出 No。
10000 0
No
5 6 1 2 2 3 3 1 1 4 4 5 5 1
Yes
对于所有测试数据，$1\le n \le 10^4$，$1\le m \le 10^6$。
| 子任务编号 | $n\leq$ | 分值 |
|---|---|---|
| $1$ | $10$ | $40$ |
| $2$ | $20$ | $20$ |
| $3$ | $400$ | $20$ |
| $4$ | $10000$ | $20$ |
The discussion section is only for posting: Editorials, General Discussions (problem-solving strategies, alternative approaches), and Off-topic conversations.
This is NOT for reporting issues! If you want to report bugs or errors, please use the Issues section below.
If you find any issues with the problem (statement, scoring, time/memory limits, test cases, etc.), you may submit an issue here. A problem moderator will review your issue.
Guidelines: