Leetcode 220. Contains Duplicate III

Given an array and integers indexDiff and valueDiff, determine whether there exist distinct indices i and j with |i - j| ≤ indexDiff and |nums[i] - nums[j]| ≤ valueDiff. The core challenge is maintaining a sliding window of the last indexDiff values and quickly detecting any value within valueDiff of the current element (often solved using an ordered set or bucketization).