// This implementation uses separate
// chaining to handle collisions
public class HashStringSetV2 {
   private HashStringNode[] hashTable;
   private int size;
   
   // Constructs a new, empty set with the given underlying capacity
   public HashStringSetV2(int capacity) {
      hashTable = new HashStringNode[capacity];
      size = 0;
   }
   
   // Given a element, returns the index at which the element should be in
   private int hashIndex(String element) {
      int index = Math.abs(element.hashCode() % hashTable.length);
      return index;
   }
   
   // Returns true if this set contains the specified element and false otherwise
   public boolean contains(String element) {
      int index = hashIndex(element);
      HashStringNode curr = hashTable[index];
      
      // Search the list for the given element
      while (curr != null) {
         if (curr.data.equals(element)) {
            return true;
         }
         curr = curr.next;
      }
      return false;
   }
   
   // Adds the specified element to this set if it is not already present.
   // Returns true if the element was not already present and false otherwise
   public boolean add(String element) {
      if (contains(element)) {
         return false;
      }
      // Find the list that the given element should be in
      int index = hashIndex(element);
      
      // Add the element to the front of the list
      hashTable[index] = new HashStringNode(element, hashTable[index]);
      size++;
      return true;
   }
   
   // Removes the specified element from this set if it is present.
   // Returns true if the element was present and false otherwise
   public boolean remove(String element) {
      if (!contains(element)) {
         return false;
      }
      // Find the list that the given element is in
      int index = hashIndex(element);
      
      // Remove the given element from that list
      HashStringNode curr = hashTable[index];
      if (curr != null && curr.data.equals(element)) {
         hashTable[index] = hashTable[index].next;
      } else {
         while (curr != null && curr.next != null) {
            if (curr.next.data.equals(element)) {
               curr.next = curr.next.next;
            }
            curr = curr.next;
         }
      }
      size--;
      return true;
   }
   
   // Returns the number of elements in this set
   public int size() {
      return this.size;
   }
   
   // Returns true if this set contains no elements
   public boolean isEmpty() {
      return this.size == 0;
   } 
   
   // Node class to store lists in hashTable
   private static class HashStringNode {
      public String data;
      public HashStringNode next;
      
      public HashStringNode(String data, HashStringNode next) {
         this.data = data;
         this.next = next;
      }
   }
}