SDE - 1

A palindrome string is one that reads the same backward as well as forward.

You are given a string 'str'.

Find the minimum number of characters needed to insert in 'str' to make it a palindromic string.

Example :

Input: 'str' = "abca"

Output: 1

Explanation:
If we insert the character ‘b’ after ‘c’, we get the string "abcba", which is a palindromic string. Please note that there are also other ways possible.

Ninja is stuck in a maze which is in a form of a binary tree. He needs your help in order to get out.

Ninja is presently at the node ‘X’. The only exit points of the maze are the leaf nodes of the tree. You need to tell him the distance to the nearest exit point from his current location. This will help him decide which path he should take in order to escape from the maze.

Example:

Suppose, Ninja is stuck at node 62. The possible exit points in the maze are: 40, 10, and 20. From all the possible exit points the closest ones are 10 and 20 which are at a distance of 1 unit.

You have been given two singly Linked Lists, where each of them represents a positive number without any leading zeros.

Your task is to add these two numbers and print the summation in the form of a linked list.

Example:

If the first linked list is 1 -> 2 -> 3 -> 4 -> 5 -> NULL and the second linked list is 4 -> 5 -> NULL.

The two numbers represented by these two lists are 12345 and 45, respectively. So, adding these two numbers gives 12390. 

So, the linked list representation of this number is 1 -> 2 -> 3 -> 9 -> 0 -> NULL.

You are given an array of integers 'ARR' of length 'N' and an integer Target. Your task is to return all pairs of elements such that they add up to Target.

Note:

We cannot use the element at a given index twice.

Follow Up:

Try to do this problem in O(N) time complexity. 

You are given an array of integers. You need to sort the array in ascending order using quick sort.

Quick sort is a divide and conquer algorithm in which we choose a pivot point and partition the array into two parts i.e, left and right. The left part contains the numbers smaller than the pivot element and the right part contains the numbers larger than the pivot element. Then we recursively sort the left and right parts of the array.

Example:

Let the array = [ 4, 2, 1, 5, 3 ]
Let pivot to be the rightmost number.

After the 1st level partitioning the array will be { 2, 1, 3, 4, 5 } as 3 was the pivot. After 2nd level partitioning the array will be { 1, 2, 3, 4, 5 } as 1 was the pivot for the left part and 5 was the pivot for the right part. Now our array is sorted and there is no need to divide it again.

Given a sequence of numbers ‘ARR’. Your task is to return a sorted sequence of ‘ARR’ in non-descending order with help of the merge sort algorithm.

Example :

Merge Sort Algorithm -

Merge sort is a Divide and Conquer based Algorithm. It divides the input array into two-parts, until the size of the input array is not ‘1’. In the return part, it will merge two sorted arrays a return a whole merged sorted array.

The above illustrates shows how merge sort works.

Note :

It is compulsory to use the ‘Merge Sort’ algorithm.

You have been given an arbitrary binary tree and a node of this tree. You need to find the inorder successor of this node in the tree.

The inorder successor of a node in a binary tree is that node that will be visited immediately after the given node in the inorder traversal of the tree. If the given node is visited last in the inorder traversal, then its inorder successor is NULL.

The inorder traversal of a binary tree is the traversal method in which for any node its left subtree is visited first, then the node itself, and then the right subtree.

Note

1. Each node is associated with a unique integer value. 

2. The node for which the successor is to be found is guaranteed to be part of the tree.

You have been given a Binary Tree of 'N' nodes, where the nodes have integer values. Your task is to print the zigzag traversal of the given tree.

Note:

In zigzag order, level 1 is printed from left to right fashion, level 2 is printed from right to left. and level 3 is printed from left to right again, and so on…..

For example:

For the given binary tree

The zigzag  traversal is [1, 4, 3, 5, 2, 7, 6]

A person has 3000 bananas and a camel. He wants to transport the maximum number of bananas to a destination 1000 KMs away, using only the camel as a mode of transportation. The camel cannot carry more than 1000 bananas at a time and eats a banana every km it travels. What is the maximum number of bananas that can be transferred to the destination using only camel (no other mode of transportation is allowed).