# Category: Groupon

## Majority Element – Part 1

Objective:  Given an array of integer write an algorithm to find the majority element in it (if exist). Majority Element: If an element appears more than n/2 times in array where n is the size...

## Reverse a Linked List in groups of given size ‘K’

Objective: Given a linked list and integer ‘k’, write an algorithm to reverse the linked list in groups of size ‘k’. Example: Approach: Earlier we have seen how to reverse a linked list, solution...

## Dynamic Programming — Longest Palindromic Subsequence

Objective: Given a string, find a longest palindromic subsequence in it. What is Longest Palindromic Subsequence: A longest palindromic subsequence is a sequence that appears in the same relative order, but not necessarily contiguous(not...

## Reverse Level Order Traversal

Objective: – Given a binary tree, Do the reverse level order traversal. In our earlier post we have seen normal Level Order Traversal. In reverse level order traversal we first need to print the...

## Swap Kth Node from the front with the Kth Node from the End

Objective: Given a Linked List and a number k, Swap Kth Node from the front with the Kth Node from the End Example: ->10->20->30->40->50->60->70 Swapping 1 Node from the Front and from the End...

## Construct a binary tree from given Inorder and Postorder Traversal

Objective: – Given a inorder and postorder traversal, write an algorithm to construct a binary tree from that. This problem was asked in the Microsoft coding competition. Input: Inorder and postorder traversals Similar Problems:...

## Determine whether given binary tree is binary search tree(BST) or not

Objective: Given a Binary tree, find out whether its binary search tree or not. Input: A Binary Tree. Output: True or false based on whether tree is BST ot not. Approach: Method 1 :...