Frog Jump With K Steps

The same frog, but from stone i it can jump to any stone from i + 1 to i + k. Return the smallest total cost. If you worked out Frog Jump, this is a two-line change.

Examples

Example 1

Input:  heights = [10, 30, 40, 50, 20], k = 3
Output: 30

0 → 1 (cost 20) → 4 (cost 10) = 30.