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@ -3,191 +3,194 @@ package DataStructures.HashMap.Hashing;
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import java.util.*;
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/**
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* This class is an implementation of a hash table using linear probing
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* It uses a dynamic array to lengthen the size of the hash table when
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* load factor > .7
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* This class is an implementation of a hash table using linear probing It uses a dynamic array to
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* lengthen the size of the hash table when load factor > .7
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*/
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public class HashMapLinearProbing {
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private int hsize; //size of the hash table
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private Integer[] buckets; //array representing the table
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private Integer AVAILABLE;
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private int size; //amount of elements in the hash table
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private int hsize; // size of the hash table
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private Integer[] buckets; // array representing the table
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private Integer AVAILABLE;
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private int size; // amount of elements in the hash table
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/**
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* Constructor initializes buckets array, hsize, and creates dummy object for AVAILABLE
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* @param hsize the desired size of the hash map
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*/
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public HashMapLinearProbing(int hsize) {
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this.buckets = new Integer[hsize];
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this.hsize = hsize;
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this.AVAILABLE = new Integer(Integer.MIN_VALUE);
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this.size = 0;
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}
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/**
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* The Hash Function takes a given key and finds an index based on its data
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* @param key the desired key to be converted
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* @return int an index corresponding to the key
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*/
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public int hashing(int key) {
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int hash = key % hsize;
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if (hash < 0) {
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hash += hsize;
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}
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return hash;
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}
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/**
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* inserts the key into the hash map by wrapping it as an Integer object
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* @param key the desired key to be inserted in the hash map
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*/
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public void insertHash(int key) {
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Integer wrappedInt = new Integer(key);
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int hash = hashing(key);
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if(isFull()) {
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System.out.println("Hash table is full");
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return;
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}
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for (int i = 0;i < hsize; i++) {
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if(buckets[hash] == null || buckets[hash] == AVAILABLE) {
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buckets[hash] = wrappedInt;
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size++;
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return;
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}
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if(hash + 1 < hsize) {
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hash++;
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} else {
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hash = 0;
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}
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}
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}
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/**
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* deletes a key from the hash map and adds an available placeholder
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* @param key the desired key to be deleted
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*/
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public void deleteHash(int key) {
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Integer wrappedInt = new Integer(key);
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int hash = hashing(key);
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/**
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* Constructor initializes buckets array, hsize, and creates dummy object for AVAILABLE
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*
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* @param hsize the desired size of the hash map
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*/
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public HashMapLinearProbing(int hsize) {
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this.buckets = new Integer[hsize];
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this.hsize = hsize;
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this.AVAILABLE = new Integer(Integer.MIN_VALUE);
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this.size = 0;
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}
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if(isEmpty()) {
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System.out.println("Table is empty");
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return;
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/**
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* The Hash Function takes a given key and finds an index based on its data
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*
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* @param key the desired key to be converted
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* @return int an index corresponding to the key
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*/
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public int hashing(int key) {
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int hash = key % hsize;
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if (hash < 0) {
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hash += hsize;
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}
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return hash;
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}
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/**
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* inserts the key into the hash map by wrapping it as an Integer object
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*
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* @param key the desired key to be inserted in the hash map
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*/
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public void insertHash(int key) {
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Integer wrappedInt = new Integer(key);
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int hash = hashing(key);
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if (isFull()) {
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System.out.println("Hash table is full");
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return;
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}
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for (int i = 0; i < hsize; i++) {
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if (buckets[hash] == null || buckets[hash] == AVAILABLE) {
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buckets[hash] = wrappedInt;
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size++;
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return;
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}
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if (hash + 1 < hsize) {
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hash++;
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} else {
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hash = 0;
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}
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}
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}
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/**
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* deletes a key from the hash map and adds an available placeholder
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*
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* @param key the desired key to be deleted
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*/
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public void deleteHash(int key) {
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Integer wrappedInt = new Integer(key);
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int hash = hashing(key);
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if (isEmpty()) {
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System.out.println("Table is empty");
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return;
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}
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for (int i = 0; i < hsize; i++) {
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if (buckets[hash] != null && buckets[hash].equals(wrappedInt)) {
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buckets[hash] = AVAILABLE;
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size--;
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return;
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}
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if (hash + 1 < hsize) {
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hash++;
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} else {
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hash = 0;
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}
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}
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System.out.println("Key " + key + " not found");
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}
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/** Displays the hash table line by line */
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public void displayHashtable() {
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for (int i = 0; i < hsize; i++) {
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if (buckets[i] == null || buckets[i] == AVAILABLE) {
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System.out.println("Bucket " + i + ": Empty");
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} else {
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System.out.println("Bucket " + i + ": " + buckets[i].toString());
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}
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}
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}
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/**
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* Finds the index of location based on an inputed key
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*
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* @param key the desired key to be found
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* @return int the index where the key is located
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*/
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public int findHash(int key) {
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Integer wrappedInt = new Integer(key);
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int hash = hashing(key);
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if (isEmpty()) {
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System.out.println("Table is empty");
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return -1;
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}
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for (int i = 0; i < hsize; i++) {
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try {
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if (buckets[hash].equals(wrappedInt)) {
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buckets[hash] = AVAILABLE;
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return hash;
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}
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for(int i = 0;i < hsize; i++) {
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if(buckets[hash] != null && buckets[hash].equals(wrappedInt)) {
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buckets[hash] = AVAILABLE;
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size--;
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return;
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}
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if(hash + 1 < hsize) {
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hash++;
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} else {
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hash = 0;
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}
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}
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System.out.println("Key " + key + " not found");
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} catch (Exception E) {
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}
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if (hash + 1 < hsize) {
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hash++;
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} else {
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hash = 0;
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}
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}
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/**
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* Displays the hash table line by line
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*/
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public void displayHashtable() {
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for (int i = 0; i < hsize; i++) {
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if(buckets[i] == null || buckets[i] == AVAILABLE) {
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System.out.println("Bucket " + i + ": Empty");
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} else {
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System.out.println("Bucket " + i + ": " + buckets[i].toString());
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}
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}
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System.out.println("Key " + key + " not found");
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return -1;
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}
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private void lengthenTable() {
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buckets = Arrays.copyOf(buckets, hsize * 2);
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hsize *= 2;
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System.out.println("Table size is now: " + hsize);
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}
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/**
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* Checks the load factor of the hash table if greater than .7, automatically lengthens table to
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* prevent further collisions
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*/
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public void checkLoadFactor() {
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double factor = (double) size / hsize;
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if (factor > .7) {
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System.out.println("Load factor is " + factor + ", lengthening table");
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lengthenTable();
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} else {
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System.out.println("Load factor is " + factor);
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}
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/**
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* Finds the index of location based on an inputed key
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* @param key the desired key to be found
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* @return int the index where the key is located
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*/
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public int findHash(int key) {
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Integer wrappedInt = new Integer(key);
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int hash = hashing(key);
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if(isEmpty()) {
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System.out.println("Table is empty");
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return -1;
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}
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for(int i = 0;i < hsize; i++) {
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try {
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if(buckets[hash].equals(wrappedInt)) {
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buckets[hash] = AVAILABLE;
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return hash;
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}
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} catch (Exception E) {}
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if(hash + 1 < hsize) {
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hash++;
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} else {
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hash = 0;
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}
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}
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System.out.println("Key " + key + " not found");
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return -1;
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}
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/**
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* isFull returns true if the hash map is full and false if not full
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*
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* @return boolean is Empty
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*/
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public boolean isFull() {
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boolean response = true;
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for (int i = 0; i < hsize; i++) {
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if (buckets[i] == null || buckets[i] == AVAILABLE) {
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response = false;
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break;
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}
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}
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private void lengthenTable() {
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buckets = Arrays.copyOf(buckets, hsize * 2);
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hsize *= 2;
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System.out.println("Table size is now: " + hsize);
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}
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/**
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* Checks the load factor of the hash table
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* if greater than .7, automatically lengthens table
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* to prevent further collisions
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*/
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public void checkLoadFactor() {
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double factor = (double) size / hsize;
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if(factor > .7) {
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System.out.println("Load factor is " + factor + ", lengthening table");
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lengthenTable();
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} else {
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System.out.println("Load factor is " + factor);
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}
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}
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/**
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* isFull returns true if the hash map is full and false if not full
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* @return boolean is Empty
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*/
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public boolean isFull() {
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boolean response = true;
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for(int i = 0; i< hsize;i++) {
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if(buckets[i] == null || buckets[i] == AVAILABLE) {
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response = false;
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break;
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}
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}
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return response;
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}
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/**
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* isEmpty returns true if the hash map is empty and false if not empty
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* @return boolean is Empty
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*/
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public boolean isEmpty() {
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boolean response = true;
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for(int i = 0; i< hsize;i++) {
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if(buckets[i] != null) {
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response = false;
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break;
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}
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}
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return response;
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return response;
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}
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/**
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* isEmpty returns true if the hash map is empty and false if not empty
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*
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* @return boolean is Empty
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*/
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public boolean isEmpty() {
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boolean response = true;
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for (int i = 0; i < hsize; i++) {
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if (buckets[i] != null) {
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response = false;
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break;
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}
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}
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return response;
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}
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}
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