MyHashSet.java

//Design a Hash Set - Double Hashing Solution
//Time Complexity : O(1)
//Space Complexity : O(n)

public class MyHashSet {
 boolean[][] set;
 int pbucket;
 int sbucket;

 public MyHashSet() {
 this.pbucket = 1000;
 this.sbucket = 1000;
 this.set = new boolean[pbucket][];
 }

 public void add(int key) {
 int hash1 = key%pbucket;
 if(set[hash1] == null) {
 //initiate the array
 if(hash1 == 0)
 set[hash1] = new boolean[sbucket+1];
 else
 set[hash1] = new boolean[sbucket];
 }
 int hash2 = key/sbucket;
 set[hash1][hash2] = true;
 }

 public void remove(int key) {
 int hash1 = key%pbucket;
 if(set[hash1] != null) {
 int hash2 = key/sbucket;
 set[hash1][hash2] = false;
 }
 }

 public boolean contains(int key) {
 int hash1 = key%pbucket;
 if(set[hash1] == null) {
 return false;
 }
 int hash2 = key/sbucket;
 return set[hash1][hash2];
 }
}