1053. Previous Permutation With One Swap
https://leetcode.com/problems/previous-permutation-with-one-swap
Description
Given an array of positive integers arr
(not necessarily distinct), return the lexicographically largest permutation that is smaller than arr
, that can be made with exactly one swap (A swap exchanges the positions of two numbers arr[i]
and arr[j]
). If it cannot be done, then return the same array.
Example 1:
**Input:** arr = [3,2,1]
**Output:** [3,1,2]
**Explanation:** Swapping 2 and 1.
Example 2:
**Input:** arr = [1,1,5]
**Output:** [1,1,5]
**Explanation:** This is already the smallest permutation.
Example 3:
**Input:** arr = [1,9,4,6,7]
**Output:** [1,7,4,6,9]
**Explanation:** Swapping 9 and 7.
Example 4:
**Input:** arr = [3,1,1,3]
**Output:** [1,3,1,3]
**Explanation:** Swapping 1 and 3.
Constraints:
1 <= arr.length <= 104
1 <= arr[i] <= 104
ac
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