Contains Duplicate II LeetCode Solution

Here, We see Contains Duplicate II problem Solution. This Leetcode problem is done in many programming languages like C++, Java, JavaScript, Python, etc., with different approaches.

Contains Duplicate II LeetCode Solution

Problem Statement ->

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

• C++ Solution
• Java Solution
• JavaScript Solution
• Python Solution

Contains Duplicate II Leetcode Solution C++ ->

class Solution {
public:
    bool containsNearbyDuplicate(vector<int>& nums, int k)
    {
       unordered_set<int> s;
       
       if (k <= 0) return false;
       if (k >= nums.size()) k = nums.size() - 1;
       
       for (int i = 0; i < nums.size(); i++)
       {
           if (i > k) s.erase(nums[i - k - 1]);
           if (s.find(nums[i]) != s.end()) return true;
           s.insert(nums[i]);
       }
       
       return false;
    }
};
Code language: C++ (cpp)

Contains Duplicate II Leetcode Solution Java ->

class Solution {
    public boolean containsNearbyDuplicate(int[] nums, int k) {
        Set<Integer> set = new HashSet<Integer>();
        for(int i = 0; i < nums.length; i++){
            if(i > k) set.remove(nums[i-k-1]);
            if(!set.add(nums[i])) return true;
        }
        return false;
 }
}
Code language: Java (java)

Contains Duplicate II Leetcode Solution JavaScript ->

var containsNearbyDuplicate = function(nums, k) {
    const hasmap = new Map();
    for (let idx = 0; idx < nums.length; idx++) {
        if (idx - hasmap.get(nums[idx]) <= k) {
            return true;
        }
        hasmap.set(nums[idx], idx);
    }
    return false;
};
Code language: JavaScript (javascript)

Contains Duplicate II Leetcode Solution Python ->

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
            dic[v] = i
        return False
Code language: Python (python)