1425. Constrained Subsequence Sum

https://leetcode.com/problems/constrained-subsequence-sum

Description

Given an integer array nums and an integer k, return the maximum sum of a non-empty subsequence of that array such that for every two consecutive integers in the subsequence, nums[i] and nums[j], where i < j, the condition j - i <= k is satisfied.

A subsequence of an array is obtained by deleting some number of elements (can be zero) from the array, leaving the remaining elements in their original order.

Example 1:

**Input:** nums = [10,2,-10,5,20], k = 2
**Output:** 37
**Explanation:** The subsequence is [10, 2, 5, 20].

Example 2:

**Input:** nums = [-1,-2,-3], k = 1
**Output:** -1
**Explanation:** The subsequence must be non-empty, so we choose the largest number.

Example 3:

**Input:** nums = [10,-2,-10,-5,20], k = 2
**Output:** 23
**Explanation:** The subsequence is [10, -2, -5, 20].

Constraints:

• 1 <= k <= nums.length <= 105

• -104 <= nums[i] <= 104

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