Previous Permutation With One Swap
Given an array A of positive integers (not necessarily distinct), return the lexicographically largest permutation that is smaller than A, that can be made with one swap (A swap exchanges the positions of two numbers A[i] and A[j]). If it cannot be done, then return the same array.
Input: [3,2,1] Output: [3,1,2] Explanation: Swapping 2 and 1.
Input: [1,1,5] Output: [1,1,5] Explanation: This is already the smallest permutation.
Input: [1,9,4,6,7] Output: [1,7,4,6,9] Explanation: Swapping 9 and 7.
Input: [3,1,1,3] Output: [1,3,1,3] Explanation: Swapping 1 and 3.
- 1 <= A.length <= 10000
- 1 <= A[i] <= 10000
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