# 04.02.2025 [1800. Maximum Ascending Subarray Sum]

Max increasing subarray sum #easy

04.02.2025

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Problem TLDR

Max increasing subarray sum #easy

Intuition

Use brute-force, two-pointers or running sum.

Approach

• Rust has a nice chunk_by

Complexity

• Time complexity: $$O(n)$$

• Space complexity: $$O(1)$$

Code

    fun maxAscendingSum(nums: IntArray) =
        nums.indices.maxOf { i -> 
            var j = i + 1; while (j < nums.size && nums[j] > nums[j - 1]) j++
            nums.slice(i..<j).sum()
        }

    pub fn max_ascending_sum(nums: Vec<i32>) -> i32 {
        nums.chunk_by(|a, b| a < b).map(|c| c.iter().sum()).max().unwrap()
    }

    int maxAscendingSum(vector<int>& n) {
        int r = n[0];
        for (int i = 1, s = n[0]; i < size(n); ++i)
            r = max(r, s = n[i - 1] < n[i] ? s + n[i] : n[i]);
        return r;
    }