1800. Maximum Ascending Subarray Sum

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.

Example 4:

Input: nums = [100,10,1]
Output: 100

 

Constraints:

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

Rust Solution

struct Solution;

impl Solution {
    fn max_ascending_sum(nums: Vec<i32>) -> i32 {
        let n = nums.len();
        let mut max = nums[0];
        let mut sum = nums[0];
        for i in 1..n {
            if nums[i] > nums[i - 1] {
                sum += nums[i];
            } else {
                sum = nums[i];
            }
            max = max.max(sum);
        }
        max
    }
}

#[test]
fn test() {
    let nums = vec![10, 20, 30, 5, 10, 50];
    let res = 65;
    assert_eq!(Solution::max_ascending_sum(nums), res);
    let nums = vec![10, 20, 30, 40, 50];
    let res = 150;
    assert_eq!(Solution::max_ascending_sum(nums), res);
    let nums = vec![12, 17, 15, 13, 10, 11, 12];
    let res = 33;
    assert_eq!(Solution::max_ascending_sum(nums), res);
}

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