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Ray
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Add HashMapLinearProbing.java and MainLinearProbing.java
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‎DataStructures/HashMap/Hashing/HashMapLinearProbing.java‎

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package DataStructures.HashMap.Hashing;
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/**
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* This class is an implementation of a hash table using linear probing
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*
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*/
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class HashMapLinearProbing {
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private int hsize;
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private Integer[] buckets;
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private Integer AVAILABLE;
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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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buckets = new Integer[hsize];
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this.hsize = hsize;
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AVAILABLE = new Integer(Integer.MIN_VALUE);
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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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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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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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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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/**
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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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}
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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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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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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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* @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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}
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}

‎DataStructures/HashMap/Hashing/MainLinearProbing.java‎

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package DataStructures.HashMap.Hashing;
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import java.util.Scanner;
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public class MainLinearProbing {
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public static void main(String[] args) {
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int choice, key;
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HashMapLinearProbing h = new HashMapLinearProbing(7);
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Scanner In = new Scanner(System.in);
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while (true) {
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System.out.println("Enter your Choice :");
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System.out.println("1. Add Key");
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System.out.println("2. Delete Key");
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System.out.println("3. Print Table");
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System.out.println("4. Exit");
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System.out.println("5. Search and print key index");
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choice = In.nextInt();
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switch (choice) {
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case 1: {
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System.out.println("Enter the Key: ");
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key = In.nextInt();
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h.insertHash(key);
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break;
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}
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case 2: {
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System.out.println("Enter the Key delete: ");
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key = In.nextInt();
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h.deleteHash(key);
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break;
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}
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case 3: {
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System.out.println("Print table");
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h.displayHashtable();
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break;
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}
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case 4: {
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In.close();
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return;
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}
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case 5: {
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System.out.println("Enter the Key to find and print: ");
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key = In.nextInt();
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System.out.println("Key: "+ key + " is at index: "+ h.findHash(key));
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}
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}
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}
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}
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}

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