1800. Maximum Ascending Subarray Sum

Description

Given an array of positive integers nums, return the maximum possible sum of an ascending subarray in nums.

A subarray is defined as a contiguous sequence of numbers in an array.

A subarray [numsl, numsl+1, ..., numsr-1, numsr] is ascending if for all i where l <= i < r, numsi < numsi+1. Note that a subarray of size 1 is ascending.

 

Example 1:

Input: nums = [10,20,30,5,10,50]
Output: 65
Explanation: [5,10,50] is the ascending subarray with the maximum sum of 65.

Example 2:

Input: nums = [10,20,30,40,50]
Output: 150
Explanation: [10,20,30,40,50] is the ascending subarray with the maximum sum of 150.

Example 3:

Input: nums = [12,17,15,13,10,11,12]
Output: 33
Explanation: [10,11,12] is the ascending subarray with the maximum sum of 33.

 

Constraints:

• 1 <= nums.length <= 100
• 1 <= nums[i] <= 100

 

Solutions

Solution: Brute Force

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

 

JavaScript

/**
 * @param {number[]} nums
 * @return {number}
 */
const maxAscendingSum = function (nums) {
  const n = nums.length;
  let sum = nums[0];
  let result = nums[0];

  for (let index = 1; index < n; index++) {
    const prevNum = nums[index - 1];
    const num = nums[index];

    sum = num > prevNum ? sum + num : num;
    result = Math.max(sum, result);
  }
  return result;
};