package com.hit.basmath.learn.hash_table;

import java.util.HashSet;
import java.util.Set;

/**
 * 219. Contains Duplicate II
 * <p>
 * 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.
 * <p>
 * Example 1:
 * <p>
 * Input: nums = [1,2,3,1], k = 3
 * Output: true
 * <p>
 * Example 2:
 * <p>
 * Input: nums = [1,0,1,1], k = 1
 * Output: true
 * <p>
 * Example 3:
 * <p>
 * Input: nums = [1,2,3,1,2,3], k = 2
 * Output: false
 */
public class _219 {
    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;
    }
}