class Solution:
    def maxSubArray(self, nums):
        max_val = -1000000000000
        current = -1000000000000
        for n in nums:
            current = max(n, n + current)
            max_val = max(max_val, current)
        return max_val

s = Solution()
print(s.maxSubArray([8, -19, 5, -4, 20]))