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CF1896A.Jagged Swaps
Jagged Swaps
You are given a permutation of size . You can do the following operation
- Select an index from to such that and . Swap and .
Determine whether it is possible to sort the permutation after a finite number of operations.
A permutation is an array consisting of distinct integers from to in arbitrary order. For example, is a permutation, but is not a permutation ( appears twice in the array) and is also not a permutation ( but there is in the array).
Input
Each test contains multiple test cases. The first line contains the number of test cases (). Description of the test cases follows.
The first line of each test case contains a single integer () — the size of the permutation.
The second line of each test case contains integers () — the elements of permutation .
Output
For each test case, print "YES" if it is possible to sort the permutation, and "NO" otherwise.
You may print each letter in any case (for example, "YES", "Yes", "yes", "yEs" will all be recognized as positive answer).
Note
In the first test case, the permutation is already sorted.
In the second test case, we can choose index as and to form . Then, we can choose index as and to form .
In the third test case, it can be proven that it is impossible to sort the permutation.
Samples
6
3
1 2 3
5
1 3 2 5 4
5
5 4 3 2 1
3
3 1 2
4
2 3 1 4
5
5 1 2 3 4
YES
YES
NO
NO
NO
NO
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