Software Developer

You are given a square matrix of non-negative integers of size 'N x N'. Your task is to rotate that array by 90 degrees in an anti-clockwise direction without using any extra space.

For example:

For given 2D array :

    [    [ 1,  2,  3 ],
         [ 4,  5,  6 ],
         [ 7,  8,  9 ]  ]

After 90 degree rotation in anti clockwise direction, it will become:

    [   [ 3,  6,  9 ],
        [ 2,  5,  8 ],
        [ 1,  4,  7 ]   ]

You are given two strings, 'str1' and 'str2'. You have to find the length of the longest common substring.

A substring is a continuous segment of a string. For example, "bcd" is a substring of "abcd", while "acd" or "cda" are not.

Example:

Input: ‘str1’ = “abcjklp” , ‘str2’ = “acjkp”.

Output: 3

Explanation:  The longest common substring between ‘str1’ and ‘str2’ is “cjk”, of length 3.

Ninja has been given the dimensions of a matrix, count the number of paths to reach the bottom right from top left with maximum k turns allowed.

A valid turn :

There are two possible scenarios when a turn can occur at point (i, j):

Turns Right: (i - 1, j)  ->  (i, j)  ->  (i, j + 1)

Turns Down:  (i, j-1)  ->  (i, j)  ->  (i+1, j)

You are given a Singly Linked List of integers and a positive integer 'K'. Modify the linked list by reversing every alternate 'K' nodes of the linked list.

A singly linked list is a type of linked list that is unidirectional, that is, it can be traversed in only one direction from head to the last node (tail).

Note:

If the number of nodes in the list or in the last group is less than 'K', just reverse the remaining nodes. 

Example:

Linked list: 5 6 7 8 9 10 11 12
K: 3 

Output: 7 6 5 8 9 10 12 11

We reverse the first 'K' (3) nodes and then skip the next 'K'(3) nodes. Now, since the number of nodes remaining in the list (2) is less than 'K', we just reverse the remaining nodes (11 and 12). 

Note:

You need to reverse the first 'K' nodes and then skip the 'K' nodes and so on. 5 6 7 10 9 8 11 12 is not the correct answer for the given linked list.