219. Contains duplicate II

https://leetcode.com/problems/contains-duplicate-ii/

Given an integer array nums and an integer k, return true __if there are two distinct indices i and j in the array such that nums[i] == nums[j] and __abs(i - j) <= 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

Constraints:

1 <= nums.length <= 105 	
-109 <= nums[i] <= 109 	
0 <= k <= 105

  • code
class Solution {
    public boolean containsNearbyDuplicate(int[] nums, int k) {
        int mini = Math.min(k+1, nums.length);
        Set<Integer> s = new HashSet<>();
        for (int i = 0; i < nums.length; i++){
            if (s.contains(nums[i])) return true;
            s.add(nums[i]);
            if (s.size() > k) s.remove(nums[i - k]);
        }

        return false;
    }
}
  • code
class Solution:
    def containsNearbyDuplicate(self, nums, k):
        dic = {}
        for i, v in enumerate(nums):
            if v in dic and i - dic[v] <= k:
                return True
            else:
                dic[v] = i
        return False