leetcode 53. Maximum Subarray

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.

贪心：

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class Solution(object):     def maxSubArray(self, nums):         """         :type nums: List[int]         :rtype: int         """           ans = s = nums[0]         for i in xrange(1, len(nums)):             if s > 0:                 s = nums[i]+s                            else:                 s = nums[i]             ans = max(s, ans)         return ans

DP解法：//dp[i] means the maximum subarray ending with A[i];

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class Solution(object):     def maxSubArray(self, nums):         """         :type nums: List[int]         :rtype: int         """         dp = [0]*len(nums)         ans = dp[0] = nums[0]         for i in xrange(1, len(nums)):             dp[i] = max(dp[i-1]+nums[i], nums[i])             ans = max(ans, dp[i])         return ans

递归解法：

TODO