[leetcode:python]53.Maximum Subarray

题目：
Find the contiguous subarray within an array (containing at least one number) which has the largest sum.

For example, given the array [-2,1,-3,4,-1,2,1,-5,4],
the contiguous subarray [4,-1,2,1] has the largest sum = 6.
找到数组中拥有最大和的连续子序列，求这个最大和。
贪心算法
方法一：性能56ms

class Solution(object):
    def maxSubArray(self, nums):
        """
        :type nums: List[int]
        :rtype: int
        """
        thissum = 0
        maxsum = -2**31
        
        for i in range(len(nums)):
            if thissum < 0:
                thissum = 0
            thissum += nums[i]
            maxsum = max(maxsum, thissum)
        return maxsum
        

这个方法性能还可以的。。