[LeetCode] Problem 219 - Contains Duplicate II

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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

No.1

Input: nums = [1,2,3,1], k = 3

Output: true

No.2

Input: nums = [1,0,1,1], k = 1

Output: true

No.3

Input: nums = [1,2,3,1,2,3], k = 2

Output: false

Code

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public boolean containsNearbyDuplicate(int[] nums, int k) {
    Map<Integer, Integer> map = new HashMap<>();

    for (int i = 0; i < nums.length; i++) {
        if (map.containsKey(nums[i]) && i - map.get(nums[i]) <= k)
            return true;

        map.put(nums[i], i);
    }

    return false;
}