Codeforces Round 752 (Div. 2)
B
XOR Specia-LIS-t
Codeforces
1100
原题
← AC →
翻译中…

YouKn0wWho has an integer sequence $a_1, a_2, \ldots a_n$. Now he will split the sequence $a$ into one or more consecutive subarrays so that each element of $a$ belongs to exactly one subarray. Let $k$ be the number of resulting subarrays, and $h_1, h_2, \ldots, h_k$ be the lengths of the longest increasing subsequences of corresponding subarrays.

翻译中…

For example, if we split $[2, 5, 3, 1, 4, 3, 2, 2, 5, 1]$ into $[2, 5, 3, 1, 4]$, $[3, 2, 2, 5]$, $[1]$, then $h = [3, 2, 1]$.

翻译中…

YouKn0wWho wonders if it is possible to split the sequence $a$ in such a way that the bitwise XOR of $h_1, h_2, \ldots, h_k$ is equal to $0$. You have to tell whether it is possible.

翻译中…

The longest increasing subsequence (LIS) of a sequence $b_1, b_2, \ldots, b_m$ is the longest sequence of valid indices $i_1, i_2, \ldots, i_k$ such that $i_1 \lt i_2 \lt \ldots \lt i_k$ and $b_{i_1} \lt b_{i_2} \lt \ldots \lt b_{i_k}$. For example, the LIS of $[2, 5, 3, 3, 5]$ is $[2, 3, 5]$, which has length $3$.

翻译中…

An array $c$ is a subarray of an array $b$ if $c$ can be obtained from $b$ by deletion of several (possibly, zero or all) elements from the beginning and several (possibly, zero or all) elements from the end.

翻译中…

Input

翻译中…

The first line contains a single integer $t$ ($1 \le t \le 10\,000$)  — the number of test cases.

翻译中…

The first line of each test case contains a single integer $n$ ($2 \le n \le 10^5$).

翻译中…

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

翻译中…

It is guaranteed that the sum of $n$ over all test cases doesn't exceed $3 \cdot 10^5$.

翻译中…

Output

翻译中…

For each test case, print "YES" (without quotes) if it is possible to split into subarrays in the desired way, print "NO" (without quotes) otherwise. You can print each letter in any register (upper or lower).

翻译中…

Note

翻译中…

In the first test case, YouKn0wWho can split the sequence in the following way: $[1, 3, 4]$, $[2, 2]$, $[1, 5]$. This way, the LIS lengths are $h = [3, 1, 2]$, and the bitwise XOR of the LIS lengths is $3 \oplus 1 \oplus 2 = 0$.

翻译中…

In the second test case, it can be shown that it is impossible to split the sequence into subarrays that will satisfy the condition.

翻译中…

样例

Input #1
4
7
1 3 4 2 2 1 5
3
1 3 4
5
1 3 2 4 2
4
4 3 2 1
Output #1
YES
NO
YES
YES
InputCopy OutputCopy
题目信息
题号
1604B
时间限制
1 s
内存限制
256 MB

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