BinarySearch 0841 Equalize Even and Odd Index Sums

Problem statement

https://binarysearch.com/problems/Equalize-Even-and-Odd-Index-Sums/

Solution

Equal to Leetcode 1664. Ways to Make a Fair Array.

Complexity

It is O(n) for time and space.

Code

class Solution:
    def solve(self, A):
        n = len(A)
        for i in range(1, n, 2): A[i] = -A[i]
        acc = [0] + list(accumulate(A))
        return sum(acc[i+1] + acc[i] == acc[-1] for i in range(n))