CF1674D.A-B-C Sort

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题目描述

You are given three arrays aa , bb and cc . Initially, array aa consists of nn elements, arrays bb and cc are empty.

You are performing the following algorithm that consists of two steps:

  • Step 11 : while aa is not empty, you take the last element from aa and move it in the middle of array bb . If bb currently has odd length, you can choose: place the element from aa to the left or to the right of the middle element of bb . As a result, aa becomes empty and bb consists of nn elements.
  • Step 22 : while bb is not empty, you take the middle element from bb and move it to the end of array cc . If bb currently has even length, you can choose which of two middle elements to take. As a result, bb becomes empty and cc now consists of nn elements.

Refer to the Note section for examples.Can you make array cc sorted in non-decreasing order?

输入格式

The first line contains a single integer tt ( 1t21041 \le t \le 2 \cdot 10^4 ) — the number of test cases. Next tt cases follow.

The first line of each test case contains the single integer nn ( 1n21051 \le n \le 2 \cdot 10^5 ) — the length of array aa .

The second line of each test case contains nn integers a1,a2,,ana_1, a_2, \dots, a_n ( 1ai1061 \le a_i \le 10^6 ) — the array aa itself.

It's guaranteed that the sum of nn doesn't exceed 21052 \cdot 10^5 .

输出格式

For each test, print YES (case-insensitive), if you can make array cc sorted in non-decreasing order. Otherwise, print NO (case-insensitive).

输入输出样例

  • 输入#1

    3
    4
    3 1 5 3
    3
    3 2 1
    1
    7331

    输出#1

    YES
    NO
    YES

说明/提示

In the first test case, we can do the following for a=[3,1,5,3]a = [3, 1, 5, 3] :

Step 11 :

aa [3,1,5,3][3, 1, 5, 3] \Rightarrow [3,1,5][3, 1, 5] \Rightarrow [3,1][3, 1] \Rightarrow [3][3] \Rightarrow [][]

bb [][] \Rightarrow [3][\underline{3}] \Rightarrow [3,5][3, \underline{5}] \Rightarrow [3,1,5][3, \underline{1}, 5] \Rightarrow [3,3,1,5][3, \underline{3}, 1, 5]

Step 22 :

bb [3,3,1,5][3, 3, \underline{1}, 5] \Rightarrow [3,3,5][3, \underline{3}, 5] \Rightarrow [3,5][\underline{3}, 5] \Rightarrow [5][\underline{5}] \Rightarrow [][]

cc [][] \Rightarrow [1][1] \Rightarrow [1,3][1, 3] \Rightarrow [1,3,3][1, 3, 3] \Rightarrow [1,3,3,5][1, 3, 3, 5]

As a result, array c=[1,3,3,5]c = [1, 3, 3, 5] and it's sorted.

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