Question
Given a list of integers and an integer window k, decide whether the list contains two equal values that sit close together: return true if there exist indices i < j with nums[i] == nums[j] and j - i <= k, and false otherwise. For example, [1, 2, 3, 1] with k = 3 is true (the two 1s are 3 apart), but the same list with k = 2 is false. A full pairwise comparison is too slow for large inputs — aim for one pass.
has_close_duplicate(nums: list[int], k: int) → bool[[1,2,3,1],3]outtrue[[1,2,3,1],2]outfalseState your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.
Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.