3410. Maximize Subarray Sum After Removing All Occurrences of One Element

Description

You are given an integer array nums.

You can do the following operation on the array at most once:

Choose any integer x such that nums remains non-empty on removing all occurrences of x.
Remove all occurrences of x from the array.

Return the maximum subarray sum across all possible resulting arrays.

Example 1:

Input: nums = [-3,2,-2,-1,3,-2,3]

Output: 7

Explanation:

We can have the following arrays after at most one operation:

The original array is nums = [-3, 2, -2, -1, 3, -2, 3]. The maximum subarray sum is 3 + (-2) + 3 = 4.
Deleting all occurences of x = -3 results in nums = [2, -2, -1, 3, -2, 3]. The maximum subarray sum is 3 + (-2) + 3 = 4.
Deleting all occurences of x = -2 results in nums = [-3, 2, -1, 3, 3]. The maximum subarray sum is 2 + (-1) + 3 + 3 = 7.
Deleting all occurences of x = -1 results in nums = [-3, 2, -2, 3, -2, 3]. The maximum subarray sum is 3 + (-2) + 3 = 4.
Deleting all occurences of x = 3 results in nums = [-3, 2, -2, -1, -2]. The maximum subarray sum is 2.

The output is max(4, 4, 7, 4, 2) = 7.

Example 2:

Input: nums = [1,2,3,4]

Output: 10

Explanation:

It is optimal to not perform any operations.

Constraints: