Maximum Subarray Sum After at Most K Swaps

Maximum Subarray Sum After at Most K Swaps

You are given an integer array nums and an integer k.
You are allowed to perform at most k swap operations on the array.
In one swap operation, you may choose any two indices i and j and swap nums and nums[j].
Return an integer denoting the maximum possible subarray sum after performing the swaps.
 
Example 1:
Input: nums = [1,-1,0,2], k = 1
Output: 3
Explanation:

• We can swap on indices 1 and 3, resulting in the array [1, 2, 0, -1].
  
• The subarray [1, 2] has a sum of 3, which is the maximum possible subarray sum after at most k = 1​​​​​​​ swap.
  

Example 2:
Input: nums = [4,3,2,4], k = 2
Output: 13
Explanation:
The maximum possible subarray sum after at most k = 2 swaps is the sum of the entire array, which is 13.
Example 3:
Input: nums = [-1,-2], k = 0
Output: -1
Explanation:

• k = 0 swaps are allowed.
  
• The possible subarrays are [-1], [-2], and [-1, -2], with sums -1, -2, and -3 respectively.
  
• Among these sums, the maximum is -1.
  

 
Constraints:
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