MaximumSubarray.py

"""
Given an integer array nums, find the
subarray
 with the largest sum, and return its sum.



Example 1:

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

Input: nums = [1]
Output: 1
Explanation: The subarray [1] has the largest sum 1.
Example 3:

Input: nums = [5,4,-1,7,8]
Output: 23
Explanation: The subarray [5,4,-1,7,8] has the largest sum 23.


Constraints:

1 <= nums.length <= 105
-104 <= nums[i] <= 104


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: List[int]) -> int:
        if not nums:
            return 0

        max_sum = current_sum = nums[0]

        for num in nums[1:]:
            current_sum = max(num, current_sum + num)
            max_sum = max(max_sum, current_sum)

        return max_sum


nums = [-2, 1, -3, 4, -1, 2, 1, -5, 4]
solution = Solution()
max_sum = solution.maxSubArray(nums)
print(max_sum)  # Output: 6