Sword finger offer 42. maximum sum of continuous subarrays

subject

Enter an integer array , One or more consecutive integers in an array form a subarray . Find the maximum sum of all subarrays .

The required time complexity is O(n).

Example 1:

 Input : nums = [-2,1,-3,4,-1,2,1,-5,4]
 Output : 6

explain : Continuous subarray [4,-1,2,1] And the biggest , by 6.

Tips ：

1 <= arr.length <= 10^5
-100 <= arr[i] <= 100

Ideas

Dynamic programming ：

• State definition
• State turns negative
• initialization
• recursive
• end

Program

class Solution:
    def maxSubArray(self, nums: List[int]) -> int:
        dp = [0] *len(nums)
        dp[0] = nums[0]
        for i in range(1,len(nums)):
            dp[i] = dp[i-1] + nums[i] if dp[i-1]  >= 0 else  nums[i]
        return max(dp)