题目描述
An array A of length N is said to be pseudo-sorted if it can be made non-decreasing after performing the following operation at most once.
Choose an i such that 1 ≤ i ≤ N-1 and swap A_{i} and A_{i+1}
Given an array A, determine if it is pseudo-sorted or not.
------ Input Format ------
- The first line contains a single integer T - the number of test cases. Then the test cases follow.
- The first line of each test case contains an integer N - the size of the array A.
- The second line of each test case contains $N space-separated integers A_{1}, A_{2}, \dots, A_{N}$ denoting the array A.
------ Output Format ------
For each testcase, output YES if the array A is pseudo-sorted, NO otherwise.
You may print each character of YES and NO in uppercase or lowercase (for example, yes, yEs, Yes will be considered identical).
------ Constraints ------
$1 ≤ T ≤ 1000$
$2 ≤ N ≤ 10^{5}$
$1 ≤ A_{i} ≤ 10^{9}$
- Sum of $N$ over all test cases do not exceed $2 \cdot 10^{5}$
----- Sample Input 1 ------
3
5
3 5 7 8 9
4
1 3 2 3
3
3 2 1
----- Sample Output 1 ------
YES
YES
NO
----- explanation 1 ------
Test case 1: The array is already sorted in non-decreasing order.
Test case 2: We can choose $i = 2$ and swap $A_{2}$ and $A_{3}$. The resulting array will be $[1, 2, 3, 3]$, which is sorted in non-decreasing order.
Test case 3: It can be proven that the array cannot be sorted in non-decreasing order in at most one operation.
输入格式
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输出格式
见题面