https://app.codility.com/demo/results/training89YXMA-C7G/

tape_equilibrium.py

def solution(A):
    sum_a = sum(A)
    left = A[0]
    right = sum_a - left
    min_diff = abs(right - left)
   
    for idx in range(1, len(A)-1):
        cur = A[idx]
        left += cur
        right -= cur
       
        diff = abs(right - left)
        # print(idx, cur, left, right, diff, min_diff)
        if min_diff > diff:
           min_diff = diff
    
    return min_diff