class Solution: def maxLength(self , arr: List[int]) -> int: # write code here if len(arr) < 2: return len(arr) windows = {} res = 0 left = -1 for right in range(len(arr)): if arr[right] in windows: left = max(left, windows[arr[right]]) res = max(res, right - left) windows[arr[right]] = right return res