Merge operations to turn array into a palindrome

class Solution:
    def minimumOperations(self, nums: List[int]) -> int:
        left = 0
        right = len(nums) - 1
        leftsum = nums[0]
        rightsum = nums[-1]
        res = 0
        while left < right:
            # print(left, right)
            if leftsum < rightsum:
                left += 1
                leftsum += nums[left]
                res += 1
            elif leftsum > rightsum:
                right -= 1
                rightsum += nums[right]
                res += 1
            elif leftsum == rightsum:
                left += 1
                right -= 1
                leftsum = nums[left]
                rightsum = nums[right]

        return res

Merge Operations to Turn Array Into a Palindrome

You are given an array nums consisting of positive integers.

You can perform the following operation on the array any number of times:

Choose any two adjacent elements and replace them with their sum.
- For example, if nums = [1,2,3,1], you can apply one operation to make it [1,5,1].

Return the minimum number of operations needed to turn the array into a palindrome.

Example 1:

Input: nums = [4,3,2,1,2,3,1]
Output: 2
Explanation: We can turn the array into a palindrome in 2 operations as follows:
- Apply the operation on the fourth and fifth element of the array, nums becomes equal to [4,3,2,3,3,1].
- Apply the operation on the fifth and sixth element of the array, nums becomes equal to [4,3,2,3,4].
The array [4,3,2,3,4] is a palindrome.
It can be shown that 2 is the minimum number of operations needed.

Example 2:

Input: nums = [1,2,3,4]
Output: 3
Explanation: We do the operation 3 times in any position, we obtain the array [10] at the end which is a palindrome.

Constraints:

1 <= nums.length <= 10⁵
1 <= nums[i] <= 10⁶