Leetcode53 Maximum Subarray

最新推荐文章于 2021-12-20 16:36:02 发布

原创最新推荐文章于 2021-12-20 16:36:02 发布 · 128 阅读

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本文深入探讨了求解数组中具有最大和的连续子序列的经典算法问题，提供了四种解法，重点介绍了O(N)时间复杂度的高效解决方案。

描述：求数组中的连续子序列和
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.
该题属于特别经典的一道题目了，可以有4中解法，不过最好的还是DC O(N)和DP O(NlogN),自己尝试写的DP：

class Solution:
    def maxSubArray(self, nums: List[int]) -> int:
        ThisSum = 0
        MaxSum = nums[0]
        #print(MaxSum)
        for i in range(len(nums)):
            
            ThisSum += nums[i]
            while ThisSum > MaxSum:
                MaxSum = ThisSum
            if ThisSum < 0:
                ThisSum = 0#负数不用再次参与运算，舍弃
         
        return MaxSum
#时间复杂度已经是O(N)了，比分而治之的NlogN要快**加粗样式**