Codeforces Round 649 (Div. 2)
D
Ehab's Last Corollary
Codeforces
2100
原题
← CE →
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Given a connected undirected graph with $n$ vertices and an integer $k$, you have to either:

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  • either find an independent set that has exactly $\lceil\frac{k}{2}\rceil$ vertices.
  • or find a simple cycle of length at most $k$.
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An independent set is a set of vertices such that no two of them are connected by an edge. A simple cycle is a cycle that doesn't contain any vertex twice.

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I have a proof that for any input you can always solve at least one of these problems, but it's left as an exercise for the reader.

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Input

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The first line contains three integers $n$, $m$, and $k$ ($3 \le k \le n \le 10^5$, $n-1 \le m \le 2 \cdot 10^5$) — the number of vertices and edges in the graph, and the parameter $k$ from the statement.

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Each of the next $m$ lines contains two integers $u$ and $v$ ($1 \le u,v \le n$) that mean there's an edge between vertices $u$ and $v$. It's guaranteed that the graph is connected and doesn't contain any self-loops or multiple edges.

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Output

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If you choose to solve the first problem, then on the first line print $1$, followed by a line containing $\lceil\frac{k}{2}\rceil$ distinct integers not exceeding $n$, the vertices in the desired independent set.

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If you, however, choose to solve the second problem, then on the first line print $2$, followed by a line containing one integer, $c$, representing the length of the found cycle, followed by a line containing $c$ distinct integers not exceeding $n$, the vertices in the desired cycle, in the order they appear in the cycle.

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Note

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In the first sample:

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image

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Notice that printing the independent set $\{2,4\}$ is also OK, but printing the cycle $1-2-3-4$ isn't, because its length must be at most $3$.

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In the second sample:

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image

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Notice that printing the independent set $\{1,3\}$ or printing the cycle $2-1-4$ is also OK.

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In the third sample:

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image

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In the fourth sample:

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image

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样例

Input #1
4 4 3
1 2
2 3
3 4
4 1
Output #1
1
1 3
InputCopy OutputCopy
Input #2
4 5 3
1 2
2 3
3 4
4 1
2 4
Output #2
2
3
2 3 4
InputCopy OutputCopy
Input #3
4 6 3
1 2
2 3
3 4
4 1
1 3
2 4
Output #3
2
3
1 2 3
InputCopy OutputCopy
Input #4
5 4 5
1 2
1 3
2 4
2 5
Output #4
1
1 4 5
InputCopy OutputCopy
题目信息
题号
1364D
时间限制
1 s
内存限制
256 MB
标签
构造
DFS 及类似
图论
贪心
模拟
树

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。