146 lines
2.8 KiB
Java
146 lines
2.8 KiB
Java
package DataStructures.HashMap.Hashing;
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public class HashMap {
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private int hsize;
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private LinkedList[] buckets;
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public HashMap(int hsize) {
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buckets = new LinkedList[hsize];
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for (int i = 0; i < hsize; i++) {
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buckets[i] = new LinkedList();
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// Java requires explicit initialisaton of each object
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}
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this.hsize = hsize;
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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) hash += hsize;
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return hash;
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}
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public void insertHash(int key) {
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int hash = hashing(key);
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buckets[hash].insert(key);
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}
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public void deleteHash(int key) {
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int hash = hashing(key);
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buckets[hash].delete(key);
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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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System.out.printf("Bucket %d :", i);
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System.out.println(buckets[i].display());
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}
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}
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public static class LinkedList {
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private Node first;
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public LinkedList() {
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first = null;
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}
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public void insert(int key) {
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if (isEmpty()) {
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first = new Node(key);
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return;
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}
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Node temp = findEnd(first);
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temp.setNext(new Node(key));
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}
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private Node findEnd(Node n) {
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if (n.getNext() == null) {
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return n;
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} else {
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return findEnd(n.getNext());
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}
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}
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public Node findKey(int key) {
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if (!isEmpty()) {
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return findKey(first, key);
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} else {
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System.out.println("List is empty");
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return null;
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}
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}
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private Node findKey(Node n, int key) {
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if (n.getKey() == key) {
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return n;
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} else if (n.getNext() == null) {
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System.out.println("Key not found");
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return null;
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} else {
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return findKey(n.getNext(), key);
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}
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}
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public void delete(int key) {
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if (!isEmpty()) {
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if (first.getKey() == key) {
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first = null;
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} else {
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delete(first, key);
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}
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} else {
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System.out.println("List is empty");
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}
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}
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private void delete(Node n, int key) {
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if (n.getNext().getKey() == key) {
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if (n.getNext().getNext() == null) {
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n.setNext(null);
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} else {
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n.setNext(n.getNext().getNext());
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}
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}
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}
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public String display() {
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return display(first);
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}
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private String display(Node n) {
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if (n == null) {
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return "null";
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} else {
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return n.getKey() + "->" + display(n.getNext());
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}
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}
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public boolean isEmpty() {
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return first == null;
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}
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}
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public static class Node {
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private Node next;
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private int key;
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public Node(int key) {
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next = null;
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this.key = key;
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}
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public Node getNext() {
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return next;
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}
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public int getKey() {
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return key;
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}
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public void setNext(Node next) {
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this.next = next;
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}
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}
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}
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