Maximum Sum Subarray of Size K Problem

Maximum Sum Subarray of Size K Problem — ExecCode Easy DSA Practice

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Problem description

Given an array nums and an integer k, find the maximum sum among all contiguous subarrays of exactly size k. The window length never changes: first compute the sum of nums[0..k-1], then slide the window one step at a time by subtracting the outgoing left value and adding the incoming right value. This turns a repeated O(k) sum into an O(1) update per window.

Examples

Input nums = [2, 1, 5, 1, 3, 2, 4, 6], k = 3; Output 12. Input nums = [5, 2, -1, 0, 3], k = 2; Output 7. Input nums = [4, 4, 4], k = 3; Output 12

Constraints

1 ≤ k ≤ nums.length ≤ 10⁵ -10⁴ ≤ nums[i] ≤ 10⁴

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