Search for the maximum sum of a subarray with a length constraint

Rust Hard vectors

Task «Search for the maximum sum of a subarray with a length constraint»

Given an integer vector and a number k. Find the maximum sum of any subarray of length at most k. If there are multiple such subarrays, output the sum of the first one in order. Constraints: vector length from 1 to 10^5, k from 1 to the length of the vector, numbers from -10^9 to 10^9. The solution must be efficient (O(n)).

Input Format

First line: number n (vector length) and k (maximum subarray length). Second line: n integers separated by spaces.

Output Format

One integer — the maximum sum of a subarray of length at most k.

Examples

Example 1

INPUT

6 4
1 -2 3 4 -5 6

OUTPUT

8

Example 2

INPUT

delivered
[{"id":10,"status":"processing","items":[]}]

OUTPUT

[{"id":10,"status":"processing","items":[]}]

main.rs