219.contains-duplicate-ii.py

#
# @lc app=leetcode id=219 lang=python3
#
# [219] Contains Duplicate II
#


class Solution:
    def containsNearbyDuplicate(self, nums: List[int], k: int) -> bool:
        d = dict.fromkeys(nums, '#')
        for x, n in enumerate(nums):
            if d[n] == '#':
                d[n] = x
            elif d[n] <= x:
                if x - d[n] <= k:
                    return True
                else:
                    d[n] = x
        return False