3. Maximum Subarray (#53) [EASY]

Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.

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.

Example 1:

Input: nums = [-2,1,-3,4,-1,2,1,-5,4]
Output: 6
Explanation: [4,-1,2,1] has the largest sum = 6.

Example 2:

Input: nums = [1]
Output: 1

Example 3:

Input: nums = [0]
Output: 0

Example 4:

Input: nums = [-1]
Output: -1

Example 5:

Input: nums = [-2147483647]
Output: -2147483647

Constraints:

• 1 <= nums.length <= 2 * 104
• -231 <= nums[i] <= 231 - 1

https://leetcode.com/problems/maximum-subarray/

My Solution: O(n)

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

Note: Updated array stores the maximum sum of the subarray looped thru so far.