CareerCup

import java.util.HashSet;

public class NonRepeatedNum {
	public static void main(String args[])
	{
		HashSet<Integer> realSet = new HashSet<>();
		HashSet<Integer> DupeSet = new HashSet<>();
		int [] arr = {1, 2, 2, 3, 4, 5, 6, 2, 3};
		int [] arrDupe = new int[arr.length-1];
		int count = 0;
		
		
		for(int i =0;i<arr.length;i++)
		{
			arrDupe[arr[i]]++; 
		}
		for(int i = 0;i< arrDupe.length;i++)
		{
			if(arrDupe[i] == 1)
			{
				count++;
			}
		}
		System.out.println(count);
	}

}

import java.util.Comparator;
	import java.util.Iterator;
	import java.util.PriorityQueue;
	
	public class FindCheapFlights {
		public static void main(String args[]) {
			int[][] flightCharges = new int[3][2];
			flightCharges [0][0] = 500;
			flightCharges [0][1] = 600;
			flightCharges [1][0] = 300;
			flightCharges [1][1] = 400;
			flightCharges [2][0] = 700;
			flightCharges [2][1] = 900;
			findCheapFlights(flightCharges);
			
		}
	
		private static void findCheapFlights(int[][] flightCharges) {
			int countA = 0;
			int countB = 0;
			PriorityQueue<Integer> pq = new PriorityQueue<Integer>(4, (Comparator<? super Integer>) new CheapFLightComparator());
			
			for(int i = 0;i<3;i++)
			{	
				int cheapFlight = flightCharges[i][0] - flightCharges[i][1];
				if(cheapFlight<0 && countA<50)
				{
					pq.add(flightCharges[i][0]);
					System.out.println(flightCharges[i][0]+" is cheap");
					countA++;
				}
				else {
					pq.add(flightCharges[i][1]);
					System.out.println(flightCharges[i][1]+" is cheap");
					countB++;
				}				
			}
			for(Integer in : pq)
			{
				System.out.println(in);
			}
			
		}
	
	}
	 class CheapFLightComparator implements Comparator<Integer>{	
		@Override
		public int compare(Integer o1, Integer o2) {
			
				if(o1<o2)
				{
				return -1;
				}
				return 1;			
		}
	}

{{

public class SequencePrinter {

public static void main(String args[])
{
Threads T1 = new Threads("a1","a2");
Threads T2 = new Threads("b1","b2");
T1.start();
T2.start();
}

}
class Threads extends Thread
{
String s1 = null;
String s2 = null;
int count = 0;
Threads(String s1, String s2)
{
this.s1 = s1;
this.s2 = s2;
this.count = 0;
}
public void run()
{
if(count == 0)
{
System.out.println(this.s1);
count++;
this.yield();
}
if(count == 1)
{
System.out.println(this.s2);
}
}
}




}}

For a Singly linked list :

If intersecting node and the last node is equal, then it is V.... remaining possibilities are Y
By Valar & Varsha :D

public class KthElementFromTail {
	public static void main(String args[]){
		SLLImpl list = new SLLImpl();
		list.addToTail(1);
		list.addToTail(2);
		list.addToTail(3);
		list.addToTail(4);
		list.addToTail(5);
		list.addToTail(6);
		int element = getKthElementFromTail(2, list);
		System.out.println(element);
	}

	private static int getKthElementFromTail(int index, SLLImpl list) {
		int position = 1;
		SLLNode node = null;
		for(node = list.head; position != list.size - index; node=node.next){
			position++;			
		}
		return node.data;		
	}
}

public class DLLPalindrome {
	static DoublyLinkedList DLL = new DoublyLinkedList();

	public static void main(String args[])
	{
		DLLPalindrome dp = new DLLPalindrome ();
		dp.populateDLL();
		DLL.iterateForward();
		dp.isPalindrome(DLL);
	}

	private void isPalindrome(DoublyLinkedList dll) {
		for(int i=0;i<dll.getSize()/2;i++)
		{
			if(dll.head.data == dll.tail.data)
			{
			dll.head  = dll.head.next;
			dll.tail  = dll.tail.prev;
			}
			else
			{
				System.out.println("not a palindrome");
			}
		}
		
	}

	private void populateDLL() {

		DLL.addDataToFirst(4);
		DLL.addDataToFirst(5);
		DLL.addDataToLast(4);
		DLL.addDataToLast(5);

	}
	
}