Merge pull request #423 from shivg7706/master

adding seprate chaining

Data Structures/HashMap/Hashing/HashMap.java

@@ -0,0 +1,39 @@
+class HashMap {
+	private int hsize;
+	private LinkedList[] buckets;
+
+	public HashMap(int hsize) {
+		buckets = new LinkedList[hsize];
+		for (int i = 0; i < hsize ; i++ ) {
+			buckets[i] = new LinkedList();
+			// Java requires explicit initialisaton of each object 
+		}
+		this.hsize = hsize;
+	}
+
+	public int hashing(int key) {
+		int hash = key % hsize;
+		if(hash < 0)
+			hash += hsize;
+		return hash;
+	}
+	
+	public void insertHash(int key) {
+		int hash = hashing(key);
+		buckets[hash].insert(key);
+	}
+
+
+	public void deleteHash(int key) {
+		int hash = hashing(key);
+
+		buckets[hash].delete(key);
+	}
+	public void displayHashtable() {
+		for (int i = 0;i < hsize ; i++) {
+			System.out.printf("Bucket %d :",i);
+			buckets[i].display();
+		}
+	}
+
+}

Data Structures/HashMap/Hashing/LinkedList.java

@@ -0,0 +1,62 @@
+class LinkedList {
+
+	private Node Head;
+	private int size;
+
+	public LinkedList() {
+		Head = null;
+		size = 0;
+	}
+
+	public void insert(int data) {
+
+		Node temp = Head;
+		Node newnode = new Node(data);
+	
+		size++;
+
+		if(Head == null) {
+			Head = newnode;
+		}
+		else {
+			newnode.next = Head;
+			Head = newnode;
+		}
+	}
+
+	public void delete(int data) {
+		if(size == 0) {
+			System.out.println("UnderFlow!");
+			return;
+		}
+
+		else {
+			Node curr = Head;
+			if (curr.data == data) {
+				Head = curr.next;
+				size--;
+				return;
+			}
+			else {
+				
+				while(curr.next.next != null) {
+					if(curr.next.data == data){
+							curr.next = curr.next.next;
+							return;
+						}
+				}
+
+				System.out.println("Key not Found");
+			}
+		}
+	}
+
+	public void display() {
+		Node temp = Head;
+		while(temp != null) {
+			System.out.printf("%d ",temp.data);
+			temp = temp.next;
+		}
+		System.out.println();
+	}
+}

Data Structures/HashMap/Hashing/Main.java

@@ -0,0 +1,45 @@
+import java.util.Scanner;
+
+public class Main {
+	public static void main(String[] args) {
+
+		int choice, key;
+
+		HashMap h = new HashMap(7);
+
+		while (true) {
+			System.out.println("Enter your Choice :");
+			System.out.println("1. Add Key");
+			System.out.println("2. Delete Key");
+			System.out.println("3. Print Table");
+			System.out.println("4. Exit");
+
+			Scanner In = new Scanner(System.in);
+
+			choice = In.nextInt();
+
+			switch (choice) {
+				case 1: {
+					System.out.println("Enter the Key: ");
+					key = In.nextInt();
+					h.insertHash(key);
+					break;
+				}
+				case 2: {
+					System.out.println("Enter the Key delete:  ");
+					key = In.nextInt();
+					h.deleteHash(key);
+					break;
+				}
+				case 3: {
+					System.out.println("Print table");
+					h.displayHashtable();
+					break;
+				}
+				case 4: {
+					return;
+				}	
+			}
+		}
+	}
+}

Data Structures/HashMap/Hashing/Node.java

@@ -0,0 +1,9 @@
+class Node {
+	int data;
+	Node next;
+
+	public Node(int data) {
+		this.data = data;
+		this.next = null;
+	}
+}