# -*- coding: utf-8 -*-

"""

Given an integer array nums, find the contiguous subarray (containing at least one number)

which has the largest sum and return its sum.

Example:

Input: [-2,1,-3,4,-1,2,1,-5,4],

Output: 6

Explanation: [4,-1,2,1] has the largest sum = 6.

Follow up:

If you have figured out the O(n) solution, try coding another solution

using the divide and conquer approach, which is more subtle.

"""

class Solution:

def maxSubArray(self, nums):

"""

:type nums: List[int]

:rtype: int

>>> s = Solution()

>>> nums = [-2,1,-3,4,-1,2,1,-5,4]

>>> s.maxSubArray(nums)

6

>>> nums1 = [-2,-1]

>>> s.maxSubArray(nums1)

-1

>>> nums2 = [2,1]

>>> s.maxSubArray(nums2)

3

Explanation: [4,-1,2,1] has the largest sum = 6.

"""

# leetcode一个人的犀利解法。服气

# for i in range(1, len(nums)):

# if nums[i-1] > 0:

# nums[i] += nums[i-1]

# return max(nums)

l = len(nums)

if l == 1:

return nums[0]

sum_ = nums[0]

max_ = nums[0]

for i in range(1, l):

sum_ = max(nums[i], sum_ + nums[i])

max_ = max(sum_, max_)

return max_

if __name__ == '__main__':

import doctest

doctest.testmod(verbose=True)