Maximum Sum Circular Subarray

class Solution:
    def maxSubarraySumCircular(self, A: List[int]) -> int:
        n = len(A)
        max_cur = A[0]
        max_total = max_cur
        for i in range(1,n):
            max_cur = max(max_cur + A[i], A[i])
            max_total = max(max_total, max_cur)

        pref = [A[0]]*n
        sum_pref = A[0]
        suf = [A[n-1]]*n
        sum_suf = A[n-1]
        for i in range(1,n):
            sum_pref += A[i]
            pref[i] = max(pref[i-1], sum_pref)
            sum_suf += A[n-1-i]
            suf[n-1-i] = max(suf[n-i], sum_suf)

        for i in range(1,n):
            if pref[i-1]+suf[i] > max_total:
                max_total = pref[i-1]+suf[i]

        return max_total