Solution: Contains Duplicate II

Statement

You are given an integer array, nums, and an integer k. Determine whether two distinct indices, i and j, are in the array, such that nums[i] == nums[j] and the absolute difference between i and j is at most k. Return TRUE if such indices exist; otherwise, return FALSE.

Constraints:

• $1 \leq$ nums.length $\leq 10^3$ ...