219. 存在重复元素 II

 

前两个超时，第三个用的set过了。

代码一：

class Solution(object):
    def containsNearbyDuplicate(self, nums, k):
        """
        :type nums: List[int]
        :type k: int
        :rtype: bool
        """
        for i in range(len(nums)):
            for j in range(i + 1, i + k + 1):
                if j < len(nums) and nums[i] == nums[j]:
                    return True
        return False

代码二：

class Solution(object):
    def containsNearbyDuplicate(self, nums, k):
        """
        :type nums: List[int]
        :type k: int
        :rtype: bool
        """
        i = 0
        j = i + 1
        while i < len(nums) and j < len(nums):
            for index in range(j, j + k):
                if index < len(nums) and nums[index] == nums[i]:
                    return True
            i += 1
            j = i + 1
        return False

代码三：

class Solution(object):
    def containsNearbyDuplicate3(self, nums, k):
        arr = {}
        for i in range(len(nums)):
            if nums[i] in arr and i - arr[nums[i]] <= k:
                return True
            arr[nums[i]] = i
        return False