题库练习 LIS or Reverse LIS?
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A15134 | LIS or Reverse LIS?

时间限制1s
内存限制256MB
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题目描述

You are given an array $a$ of $n$ positive integers.

Let $\text{LIS}(a)$ denote the length of [longest strictly increasing subsequence](https://en.wikipedia.org/wiki/Longest_increasing_subsequence) of $a$ . For example,

- $\text{LIS}([2, \underline{1}, 1, \underline{3}])$ = $2$ .
- $\text{LIS}([\underline{3}, \underline{5}, \underline{10}, \underline{20}])$ = $4$ .
- $\text{LIS}([3, \underline{1}, \underline{2}, \underline{4}])$ = $3$ .

We define array $a'$ as the array obtained after reversing the array $a$ i.e. $a' = [a_n, a_{n-1}, \ldots , a_1]$ .

The beauty of array $a$ is defined as $min(\text{LIS}(a),\text{LIS}(a'))$ .

Your task is to determine the maximum possible beauty of the array $a$ if you can rearrange the array $a$ arbitrarily.

输入格式

The input consists of multiple test cases. The first line contains a single integer $t$ $(1 \leq t \leq 10^4)$ — the number of test cases. Description of the test cases follows.

The first line of each test case contains a single integer $n$ $(1 \leq n \leq 2\cdot 10^5)$ — the length of array $a$ .

The second line of each test case contains $n$ integers $a_1,a_2, \ldots ,a_n$ $(1 \leq a_i \leq 10^9)$ — the elements of the array $a$ .

It is guaranteed that the sum of $n$ over all test cases does not exceed $2\cdot 10^5$ .

输出格式

For each test case, output a single integer — the maximum possible beauty of $a$ after rearranging its elements arbitrarily.

输入输出样例

输入 #1
3
3
6 6 6
6
2 5 4 5 2 4
4
1 3 2 2
输出 #1
1
3
2
C++ 编辑器
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输出