_219.java

package com.fishercoder.solutions;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

public class _219 {

    public static class Solution1 {
        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])) {
                    if (i - map.get(nums[i]) <= k) {
                        return true;
                    } else {
                        map.put(nums[i], i);
                    }
                } else {
                    map.put(nums[i], i);
                }
            }
            return false;
        }
    }

    public static class Solution2 {
        public boolean containsNearbyDuplicate(int[] nums, int k) {
            Set<Integer> set = new HashSet<>();
            for (int i = 0; i < nums.length; i++) {
                if (!set.add(nums[i])) {
                    return true;
                }
                if (set.size() > k) {
                    set.remove(nums[i - k]);
                }
            }
            return false;
        }
    }
}