LeetCode [219] Contains Duplicate II

 219. Contains Duplicate II

Easy

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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class Solution { public: bool containsNearbyDuplicate(vector<int>& nums, int k) { unordered_map<int, int> hash; for(int i=0; i<(int)nums.size(); ++i){ int v = nums[i]; if(hash.count(v)>0){ if(i-hash[v]<=k) return true; } hash[v] = i; } return false; } }; class Solution { public: bool containsNearbyDuplicate(vector<int>& nums, int k) { set<int> s; for(int i=0; i<(int)nums.size(); ++i){ if(i>k){ s.erase(nums[i-k-1]); } if(s.count(nums[i])) return true; s.insert(nums[i]); } return false; } };

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class Solution { public boolean containsNearbyDuplicate(int[] nums, int k) { Set<Integer> set = new HashSet<Integer>(); int l = nums.length; for(int i=0; i<l; ++i) { if(set.contains(nums[i])) return true; set.add(nums[i]); if(set.size()>k){ set.remove(nums[i-k]); } } return false; } }