thmain

public class RearrageArrayPositiveNegative {
	int[] arrA;

	public RearrageArrayPositiveNegative(int[] arrA) {
		this.arrA = arrA;
	}

	public void divideGroups(int low, int high) {
		if (low >= high)
			return;

thmain

public class CountAllPaths {

	int rowCount;
	int colCount;
	int[][] arrA;

	public CountAllPaths(int arrA[][]) {
		this.arrA = arrA;
		rowCount = arrA.length;
		colCount = arrA[0].length;

thmain

//Find the Loop
//Take two pointers, both starts from head
//move one pointer with normal speed and another with double speed
//if both pointers meets at some point, we have found the loop
//Now find the loop length
//at the point where both pointers have met, stop one pointer and keep moving the nother one
//when another pointer meets the first pointer, stop. 
//keep counting number of hops, that will your loop length
//Now To break the loop
//move one pointer by the loop length

thmain

//find the length of both the linked lists say : a_len and b_len
//find the lenDiff = (a_len ~ b_len)
//traverse the longer linked list by lenDiff
//Now traverse both the lists at the same time
//check whether nodes are same, if yes then we have found the intersection point
//if we reach the end of the link lists then there is no intersection point.
public class FindIntersectionOfLinkedLists {

	public LinkedListIntersection a;
	public LinkedListIntersection b;

thmain

public class KthToLastElementofLL {

	public int kthByRecursion(Node head, int k){
		if(head==null){
			return 0;
		}
		int i =  kthByRecursion(head.next, k)+1;
		if(i==k){
			System.out.println(head.data);
		}

thmain

public class BinaryRotate {
	
	public int rotateBinary(int number){
		int res = 0;
		while(number>0){
			res=res<<1; 		
			res = res|(number & 1); 			
			number=number>>1;
		}
		return res;

thmain

public class LinkedListAddtionReverseOrder {
	public Node add(Node h1, Node h2){
		int carry = 0;
		Node newHead = null;
		Node curr=null;
		while(h1!=null && h2!=null){
			int a = h1.data;
			int b = h2.data;
			int total = a+b+carry;
			if(total>=10){

thmain

public class NodeHeight {

	public int getNodeHeight(Node root, Node x, int height){
		if(root==null) return 0;
		if(root==x) return height;
		
		//check if the node is present in the left sub tree
		int level = getNodeHeight(root.left,x,height+1);
		//System.out.println(level);
		if(level!=0) return level;

thmain

public class BalancedTree {
	public boolean checkBalance(Node root){
		int result = isBalanced(root);
		if(result>0){
			return true;
		}else{
			return false;
		}
	}
	public int isBalanced(Node root){

thmain

public class SortedArrayToBST {
    public BSTNode convert(int [] arrA, int start, int end){
		if(start>end){
			return null;
		}
		int mid = (start + end)/2;
		BSTNode root = new BSTNode(arrA[mid]);
		root.left = convert(arrA, start, mid-1);
		root.right =convert(arrA, mid+1, end);
		return root;