LeetCode219：Contains Duplicate II

Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the absolute difference between i and j is at most k.

Example 1:

Input: nums = [1,2,3,1], k = 3
Output: true

Example 2:

Input: nums = [1,0,1,1], k = 1
Output: true

Example 3:

Input: nums = [1,2,3,1,2,3], k = 2
Output: false

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LeetCode：链接

用哈希表，如果再次在字典中出现并且index不大于k，就返回True，否则就重新赋值。

如果K个数之后还没有找到重复的，就删除字典中存储的东西，也是一种方法。

class Solution(object):
    def containsNearbyDuplicate(self, nums, k):
        """
        :type nums: List[int]
        :type k: int
        :rtype: bool
        """
        dict = {}
        for i in range(len(nums)):
            if nums[i] in dict and i - dict[nums[i]] <= k:
                return True
            dict[nums[i]] = i
        return False