Create linkedlistdriver.java

drivercode/linkedlistdriver.java

@@ -0,0 +1,231 @@
+import java.util.*;
+
+public class Main {
+
+	static class Node {
+		int val;
+		Node next;
+
+		Node() {
+			this.next = null;
+		}
+
+		Node(int val) {
+			this.val = val;
+			this.next = null;
+		}
+	}
+
+	public static void main(String[] args) {
+		Main obj = new Main();
+		System.out.println("Random array:");
+		int[] a = obj.ra(5);
+		System.out.println("Converting array to linkedlist");
+		Node outputNode = obj.convert(a);
+		obj.printList(outputNode);
+		System.out.println();
+		System.out.println("Inserting Node 777777");
+		obj.insertNode(outputNode, 777777, 3);
+		obj.printList(outputNode);
+		System.out.println();
+		System.out.println("Deleting Node");
+		obj.deleteNode(outputNode, 3);
+		obj.printList(outputNode);
+		System.out.println();
+		System.out.println("Deleting kth Node from end");
+		obj.deleteKthNodeFromEnd(outputNode, 2);
+		obj.printList(outputNode);
+		System.out.println();
+		System.out.println("Reverse list");
+		Node root = obj.reverse(outputNode);
+		obj.printList(root);
+		System.out.println();
+		System.out.println("Comparing lists");
+		boolean result = obj.areEqual(outputNode, root);
+		System.out.println(result);
+		System.out.println("Comparing lists");
+		result = obj.areEqual(root, root);
+		System.out.println(result);
+		System.out.println();
+		System.out.println("Merge two lists");
+
+		System.out.println("List 1");
+		int[] x = { 1, 3, 5, 7 };
+		Node node1 = obj.convert(x);
+		obj.printList(node1);
+		System.out.println();
+
+		System.out.println("List 2");
+		int[] y = { 2, 4, 6, 8 };
+		Node node2 = obj.convert(y);
+		obj.printList(node2);
+		System.out.println();
+
+		System.out.println("Merging...");
+		Node finalNode = obj.mergeSortedLists(node1, node2);
+		obj.printList(finalNode);
+
+	}
+
+	public static void printList(Node head) {
+		while (head != null) {
+			System.out.print(head.val + " ");
+			head = head.next;
+		}
+	}
+
+	public int[] ra(int size) {
+		Random random = new Random();
+		int arr[] = new int[size];
+		for (int i = 0; i < size; i++) {
+			arr[i] = random.nextInt();
+		}
+
+		return arr;
+	}
+
+	public Node convert(int[] arr1) {
+		Node root = new Node(arr1[0]);
+		Node current = root;
+		for (int i = 1; i < arr1.length; i++) {
+			current.next = new Node(arr1[i]);
+			current = current.next;
+		}
+		return root;
+	}
+
+	public Node insertNode(Node head, int val, int pos) {
+		if (pos < 1)
+			System.out.println("invalid position given");
+		if (pos == 1) {
+			Node tem = new Node(val);
+			tem.next = head;
+			head = tem;
+			return head;
+		}
+		int cnt = 1;
+		Node curr = head;
+		while (cnt < pos - 1) {
+			curr = curr.next;
+			cnt++;
+		}
+		Node tem = new Node(val);
+		tem.next = curr.next;
+		curr.next = tem;
+
+		return head;
+	}
+
+	Node deleteNode(Node head, int position) {
+		if (position < 0)
+			return head;
+		if (position == 1)
+			return head.next;
+		int pos = 1;
+		Node curr = head;
+		while (pos < position - 1) {
+			curr = curr.next;
+			pos++;
+		}
+		curr.next = curr.next.next;
+
+		return head;
+	}
+
+	public Boolean areEqual(Node head1, Node head2) {
+		int len1 = 0;
+		Node temp = head1;
+		while (temp != null) {
+			len1++;
+			temp = temp.next;
+		}
+		int len2 = 0;
+		temp = head2;
+		while (temp != null) {
+			len2++;
+			temp = temp.next;
+		}
+
+		if (len1 != len2) {
+			return false;
+		}
+
+		while (head1 != null && head2 != null) {
+			if (head1.val != head2.val)
+				return false;
+			head1 = head1.next;
+			head2 = head2.next;
+		}
+		/*
+		 * if(head1 == null && head2 == null){ return true; } else { return false; }
+		 */
+		return true;
+	}
+
+	// K = 1 means delete last node.
+	Node deleteKthNodeFromEnd(Node head, int k) {
+		int len = 0;
+		Node temp = head;
+		while (temp != null) {
+			len++;
+			temp = temp.next;
+		}
+		// int len=list.size(head);
+		if (k > len)
+			return head;
+		if (k == len)
+			return head.next;
+		Node curr = head;
+		Node end = head;
+		int i = 1;
+
+		while (i <= k) {
+			end = end.next;
+			i++;
+		}
+
+		while (end.next != null) {
+			curr = curr.next;
+			end = end.next;
+		}
+
+		curr.next = curr.next.next;
+
+		return head;
+	}
+
+// Reverse a linkedlist. 
+	Node reverse(Node node) {
+		Node previous = null;
+		Node curr = node;
+		Node next = null;
+
+		while (curr != null) {
+			next = curr.next;
+			curr.next = previous;
+			previous = curr;
+			curr = next;
+		}
+		node = previous;
+		return node;
+	}
+
+	Node mergeSortedLists(Node head1, Node head2) {
+
+		Node result = null;
+
+		if (head1 == null)
+			return (head2);
+		else if (head2 == null)
+			return (head1);
+		if (head1.val <= head2.val) {
+			result = head1;
+			result.next = mergeSortedLists(head1.next, head2);
+		} else {
+			result = head2;
+			result.next = mergeSortedLists(head1, head2.next);
+		}
+		return result;
+	}
+
+}