Leetcode•Sep 01, 2025
Contains Duplicate II
Hazrat Ali
Leetcode
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
Solution
/**
* @param {number[]} nums
* @param {number} k
* @return {boolean}
*/
const containsNearbyDuplicate = (nums, k) => {
const map = new Map();
for (let i = 0; i < nums.length; i++) {
const num = nums[i];
if (map.has(num) && i - map.get(num) <= k) {
return true;
}
map.set(num, i);
}
return false;
};