Codeforces Round 813 (Div. 2)
D
Empty Graph
Codeforces
2000
原题
← CE1 →
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  • — Do you have a wish?*
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  • — I want people to stop gifting each other arrays.*O_o and Another Young Boy
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An array of $n$ positive integers $a_1,a_2,\ldots,a_n$ fell down on you from the skies, along with a positive integer $k \le n$.

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You can apply the following operation at most $k$ times:

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  • Choose an index $1 \le i \le n$ and an integer $1 \le x \le 10^9$. Then do $a_i := x$ (assign $x$ to $a_i$).
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Then build a complete undirected weighted graph with $n$ vertices numbered with integers from $1$ to $n$, where edge $(l, r)$ ($1 \le l \lt r \le n$) has weight $\min(a_{l},a_{l+1},\ldots,a_{r})$.

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You have to find the maximum possible diameter of the resulting graph after performing at most $k$ operations.

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The diameter of a graph is equal to $\max\limits_{1 \le u \lt v \le n}{\operatorname{d}(u, v)}$, where $\operatorname{d}(u, v)$ is the length of the shortest path between vertex $u$ and vertex $v$.

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Input

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Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 10^4$). Description of the test cases follows.

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The first line of each test case contains two integers $n$ and $k$ ($2 \le n \le 10^5$, $1 \le k \le n$).

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The second line of each test case contains $n$ positive integers $a_1,a_2,\ldots,a_n$ ($1 \le a_i \le 10^9$).

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It is guaranteed that the sum of $n$ over all test cases does not exceed $10^5$.

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Output

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For each test case print one integer — the maximum possible diameter of the graph after performing at most $k$ operations.

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Note

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In the first test case, one of the optimal arrays is $[2,4,5]$.

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The graph built on this array:

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image

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$\operatorname{d}(1, 2) = \operatorname{d}(1, 3) = 2$ and $\operatorname{d}(2, 3) = 4$, so the diameter is equal to $\max(2,2,4) = 4$.

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样例

Input #1
6
3 1
2 4 1
3 2
1 9 84
3 1
10 2 6
3 2
179 17 1000000000
2 1
5 9
2 2
4 2
Output #1
4
168
10
1000000000
9
1000000000
InputCopy OutputCopy
题目信息
题号
1712D
时间限制
1.5 s
内存限制
256 MB
标签
二分
构造
数据结构
贪心
最短路

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。