A sensor produces readings. A reading is a glitch if the same value appears twice within k positions: there exist indices i < j with readings[i] == readings[j] and j - i <= k. Return True if a glitch exists, otherwise False.
Examples
Input: readings = [7, 3, 7], k = 2
Output: True
Input: readings = [7, 3, 7], k = 1
Output: False
Constraints
0 <= len(readings) <= 10**5,0 <= k <= 10**5- Target complexity: O(n) time.
Goals
- Store the most recent index of each value
- Check a distance condition in one pass