题库练习 K and Medians
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A14029 | K and Medians

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题目描述

Let's denote the median of a sequence $s$ with odd length as the value in the middle of $s$ if we sort $s$ in non-decreasing order. For example, let $s = [1, 2, 5, 7, 2, 3, 12]$ . After sorting, we get sequence $[1, 2, 2, \underline{3}, 5, 7, 12]$ , and the median is equal to $3$ .

You have a sequence of $n$ integers $[1, 2, \dots, n]$ and an odd integer $k$ .

In one step, you choose any $k$ elements from the sequence and erase all chosen elements except their median. These elements do not have to go continuously (gaps are allowed between them).

For example, if you have a sequence $[1, 2, 3, 4, 5, 6, 7]$ (i.e. $n=7$ ) and $k = 3$ , then the following options for the first step are possible:

- choose $[1, \underline{2}, 3]$ ; $2$ is their median, so it is not erased, and the resulting sequence is $[2, 4, 5, 6, 7]$ ;
- choose $[2, \underline{4}, 6]$ ; $4$ is their median, so it is not erased, and the resulting sequence is $[1, 3, 4, 5, 7]$ ;
- choose $[1, \underline{6}, 7]$ ; $6$ is their median, so it is not erased, and the resulting sequence is $[2, 3, 4, 5, 6]$ ;
- and several others.

You can do zero or more steps. Can you get a sequence $b_1$ , $b_2$ , ..., $b_m$ after several steps?

You'll be given $t$ test cases. Solve each test case independently.

输入格式

The first line contains a single integer $t$ ( $1 \le t \le 1000$ ) — the number of test cases.

The first line of each test case contains three integers $n$ , $k$ , and $m$ ( $3 \le n \le 2 \cdot 10^5$ ; $3 \le k \le n$ ; $k$ is odd; $1 \le m < n$ ) — the length of the sequence you have, the number of elements you choose in each step and the length of the sequence you'd like to get.

The second line of each test case contains $m$ integers $b_1, b_2, \dots, b_m$ ( $1 \le b_1 < b_2 < \dots < b_m \le n$ ) — the sequence you'd like to get, given in the ascending order.

It's guaranteed that the total sum of $n$ over all test cases doesn't exceed $2 \cdot 10^5$ .

输出格式

For each test case, print YES if you can obtain the sequence $b$ or NO otherwise. You may print each letter in any case (for example, YES, Yes, yes, yEs will all be recognized as positive answer).

输入输出样例

输入 #1
4
3 3 1
1
7 3 3
1 5 7
10 5 3
4 5 6
13 7 7
1 3 5 7 9 11 12
输出 #1
NO
YES
NO
YES
C++ 编辑器
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