You are given an integer array nums.
Split the array into exactly two subarrays, left and right, such that left is strictly increasing and right is strictly decreasing.
Return the minimum possible absolute difference between the sums of left and right. If no valid split exists, return -1.
Example 1:
Input: nums = [1,3,2]
Output: 2
Explanation:
i |
left |
right |
Validity | left sum |
right sum |
Absolute difference |
|---|---|---|---|---|---|---|
| 0 | [1] | [3, 2] | Yes | 1 | 5 | |1 - 5| = 4 |
| 1 | [1, 3] | [2] | Yes | 4 | 2 | |4 - 2| = 2 |
Thus, the minimum absolute difference is 2.
Example 2:
Input: nums = [1,2,4,3]
Output: 4
Explanation:
i |
left |
right |
Validity | left sum |
right sum |
Absolute difference |
|---|---|---|---|---|---|---|
| 0 | [1] | [2, 4, 3] | No | 1 | 9 | - |
| 1 | [1, 2] | [4, 3] | Yes | 3 | 7 | |3 - 7| = 4 |
| 2 | [1, 2, 4] | [3] | Yes | 7 | 3 | |7 - 3| = 4 |
Thus, the minimum absolute difference is 4.
Example 3:
Input: nums = [3,1,2]
Output: -1
Explanation:
No valid split exists, so the answer is -1.
Constraints:
2 <= nums.length <= 1051 <= nums[i] <= 105