Codeforces Round 922 (Div. 2)
F
Caterpillar on a Tree
Codeforces
2500
原题
← EG →
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The caterpillar decided to visit every node of the tree. Initially, it is sitting at the root.

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The tree is represented as a rooted tree with the root at the node $1$. Each crawl to a neighboring node takes $1$ minute for the caterpillar.

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And there is a trampoline under the tree. If the caterpillar detaches from the tree and falls onto the trampoline, it will end up at the root of the tree in $0$ seconds. But the trampoline is old and can withstand no more than $k$ caterpillar's falls.

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What is the minimum time the caterpillar can take to visit all the nodes of the tree?

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More formally, we need to find the minimum time required to visit all the nodes of the tree, if the caterpillar starts at the root (node $1$) and moves using two methods.

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  1. Crawl along an edge to one of the neighboring nodes: takes $1$ minute.
  2. Teleport to the root: takes no time, no new nodes become visited.
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The second method (teleportation) can be used at most $k$ times. The caterpillar can finish the journey at any node.

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Input

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The first line of the input contains two integers: $n$ ($2 \le n \le 2\cdot 10^5$) — the number of nodes in the tree, and $k$ ($0 \le k \le 10^9$) — the maximum number of teleports to the root.

翻译中…

The second line contains $n-1$ integers $p_2$, $p_3$, ..., $p_n$ ($1 \le p_i \le n$) — the ancestors in the tree for nodes $2, 3, \ldots, n$; node $1$ is the root.

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Output

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Print a single number in a single line — the minimum number of minutes required to visit all the nodes of the tree.

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Note

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The figure shows one of the ways to traverse the tree from the first test in 9 minutes.

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image

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样例

Input #1
8 1
1 1 2 2 4 3 3
Output #1
9
InputCopy OutputCopy
Input #2
4 0
4 4 1
Output #2
4
InputCopy OutputCopy
题目信息
题号
1918F
时间限制
2 s
内存限制
256 MB
标签
DFS 及类似
图论
贪心
模拟
排序
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。