JAVA EXAMPLE PROGRAMS

JAVA EXAMPLE PROGRAMS

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Program: How to reverse Singly Linked List?


Description:
Write a sample code to reverse Singly Linked List by iterating through it only once.

Recursive Method:
	1) Divide the list in two parts - first node and rest of the linked list.
	2) Call reverse for the rest of the linked list.
	3) Link rest to first.
	4) Fix head pointer.


Code:
package com.java2novice.ds.linkedlist;
 
public class SinglyLinkedListImpl<T> {
 
    private Node<T> head;
     
    public void add(T element){
         
        Node<T> nd = new Node<T>();
        nd.setValue(element);
        System.out.println("Adding: "+element);
        Node<T> tmp = head;
        while(true){
        	if(tmp == null){
                //since there is only one element, both head and 
                //tail points to the same object.
                head = nd;
                break;
            } else if(tmp.getNextRef() == null){
            	tmp.setNextRef(nd);
            	break;
            } else {
            	tmp = tmp.getNextRef();
            }
        }
    }
     
    public void traverse(){
         
        Node<T> tmp = head;
        while(true){
            if(tmp == null){
                break;
            }
            System.out.print(tmp.getValue()+"\t");
            tmp = tmp.getNextRef();
        }
    }
    
    public void reverse(){
    	
    	System.out.println("\nreversing the linked list\n");
    	Node<T> prev = null;
    	Node<T> current = head;
    	Node<T> next = null;
    	while(current != null){
    		next = current.getNextRef();
    		current.setNextRef(prev);
    		prev = current;
    		current = next;
    	}
    	head = prev;
    }
    
    public static void main(String a[]){
        SinglyLinkedListImpl<Integer> sl = new SinglyLinkedListImpl<Integer>();
        sl.add(3);
        sl.add(32);
        sl.add(54);
        sl.add(89);
        System.out.println();
        sl.traverse();
        System.out.println();
        sl.reverse();
        sl.traverse();
    }
}
 
class Node<T> implements Comparable<T> {
     
    private T value;
    private Node<T> nextRef;
     
    public T getValue() {
        return value;
    }
    public void setValue(T value) {
        this.value = value;
    }
    public Node<T> getNextRef() {
        return nextRef;
    }
    public void setNextRef(Node<T> ref) {
        this.nextRef = ref;
    }
    @Override
    public int compareTo(T arg) {
        if(arg == this.value){
            return 0;
        } else {
            return 1;
        }
    }
}

Output:
Adding: 3
Adding: 32
Adding: 54
Adding: 89

3	32	54	89	

reversing the linked list

89	54	32	3	
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List Of All Interview Programs:

  1. Remove last node of the Linked List
  2. Identify middle element of a Linked List
  3. Identify given LinkedList is a palindrom or not using Stack.
  4. Remove duplicates from sorted linked list
  5. Find Nth node from the end of Linked List
  6. Identify loop/cycle in a LinkedList.
  7. Find length of a loop in a LinkedList.
  8. Detect and remove loop in a LinkedList.
  9. How to reverse Singly Linked List?
  10. Check if given Linked List is a Circular Linked List or not.
  11. Find out duplicate number between 1 to N numbers.
  12. Find out middle index where sum of both ends are equal.
  13. Write a singleton class.
  14. Write a program to create deadlock between two threads.
  15. Write a program to reverse a string using recursive algorithm.
  16. Write a program to reverse a number.
  17. Write a program to convert decimal number to binary format.
  18. Write a program to find perfect number or not.
  19. Write a program to implement ArrayList.
  20. Write a program to find maximum repeated words from a file.
  21. Wrie a program to find out duplicate characters in a string.
  22. Write a program to find top two maximum numbers in a array.
  23. Write a program to sort a map by value.
  24. Write a program to find common elements between two arrays.
  25. How to swap two numbers without using temporary variable?
  26. Write a program to print fibonacci series.
  27. Write a program to find sum of each digit in the given number using recursion.
  28. Write a program to check the given number is a prime number or not?
  29. Write a program to find the given number is Armstrong number or not?
  30. Write a program to convert binary to decimal number.
  31. Write a program to check the given number is binary number or not?
  32. Write a program for Bubble Sort in java.
  33. Write a program for Insertion Sort in java.
  34. Write a program to implement hashcode and equals.
  35. How to get distinct elements from an array by avoiding duplicate elements?
  36. Write a program to get distinct word list from the given file.
  37. Write a program to get a line with max word count from the given file.
  38. Write a program to convert string to number without using Integer.parseInt() method.
  39. Write a program to find two lines with max characters in descending order.
  40. Write a program to find the sum of the first 1000 prime numbers.
  41. Find longest substring without repeating characters.
  42. Write a program to remove duplicates from sorted array.
  43. How to sort a Stack using a temporary Stack?
  44. Write a program to print all permutations of a given string.
  45. Implement Binary Search Tree (BST)
  46. Find min and max value from Binary Search Tree (BST)
  47. Find height of a Binary Search Tree (BST)
  48. Implement Binary Search Tree (BST) Level order traversal (breadth first).
  49. Implement Binary Search Tree (BST) pre-order traversal (depth first).
  50. Implement Binary Search Tree (BST) in-order traversal (depth first).
  51. Implement Binary Search Tree (BST) post-order traversal (depth first).
  52. How to check the given Binary Tree is Binary Search Tree (BST) or not?
  53. How to delete a node from Binary Search Tree (BST)?
  54. Write a program to find common integers between two sorted arrays.
  55. Write a program to find given two trees are mirror or not.
  56. HackerRank stack problem - Find maximum element.
  57. HackerRank stack problem - Balanced Brackets.
  58. HackerRank stack problem - Equal Stacks.
  59. HackerRank stack problem - Game Of Two Stacks.
Knowledge Centre
What is race condition?
A race condition is a situation in which two or more threads or processes are reading or writing some shared data, and the final result depends on the timing of how the threads are scheduled. Race conditions can lead to unpredictable results and subtle program bugs. A thread can prevent this from happening by locking an object. When an object is locked by one thread and another thread tries to call a synchronized method on the same object, the second thread will block until the object is unlocked.
Famous Quotations
The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails.
-- William Arthur Ward

About Author

I'm Nataraja Gootooru, programmer by profession and passionate about technologies. All examples given here are as simple as possible to help beginners. The source code is compiled and tested in my dev environment.

If you come across any mistakes or bugs, please email me to [email protected].

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