leetcode

class :
    
    def canThreePartsEqualSum(self, A: List[int]) -> bool:
        total_sum = sum(A)
        if (total_sum % 3 != 0):
            return False
        else:
            n = len(A)
            flag = total_sum / 3
            a_sum = 0
            for i in range(n-2):
                a_sum += A[i]
                if (a_sum == flag):
                    b_sum = 0
                    for j in range(i+1, n-1):
                        b_sum += A[j]
                        if (b_sum == flag):
                            if (sum(A[j+1:]) == flag):
                                return True
                            else:
                                return False
                    return False
            return False