1800. Maximum Ascending Subarray Sum - Explanation

1. Brute Force

class Solution:
    def maxAscendingSum(self, nums: List[int]) -> int:
        res = 0
        for i in range(len(nums)):
            curSum = nums[i]
            for j in range(i + 1, len(nums)):
                if nums[j] <= nums[j - 1]:
                    break
                curSum += nums[j]
            res = max(res, curSum)
        return res

Time & Space Complexity

Time complexity: $O(n ^ 2)$
Space complexity: $O(1)$

2. Iteration

class Solution:
    def maxAscendingSum(self, nums: List[int]) -> int:
        res = curSum= nums[0]

        for i in range(1, len(nums)):
            if nums[i] <= nums[i - 1]:
                curSum = 0

            curSum += nums[i]
            res = max(res, curSum)

        return res

Time & Space Complexity

Time complexity: $O(n)$
Space complexity: $O(1)$