SDE - Intern

Ninja is now bored with numbers and is now playing with characters but hates when he gets repeated characters. Ninja is provided a string, and he wants to return the first unique character in the string.The string will contain characters only from the English alphabet set, i.e., ('A' - 'Z') and ('a' - 'z'). If there is no non-repeating character, print the first character of the string. If there is no non-repeating character, return the first character of the string.

You are given a linked list of 'n' nodes and an integer 'k', where 'k' is less than or equal to 'n'.

Your task is to reverse the order of each group of 'k' consecutive nodes, if 'n' is not divisible by 'k', then the last group of nodes should remain unchanged.

For example, if the linked list is 1->2->3->4->5, and 'k' is 3, we have to reverse the first three elements, and leave the last two elements unchanged. Thus, the final linked list being 3->2->1->4->5.

Implement a function that performs this reversal, and returns the head of the modified linked list.

Example:

Input: 'list' = [1, 2, 3, 4], 'k' = 2

Output: 2 1 4 3

Explanation:
We have to reverse the given list 'k' at a time, which is 2 in this case. So we reverse the first 2 elements then the next 2 elements, giving us 2->1->4->3.

Note:

All the node values will be distinct.

You are given an arbitrary grid with M rows and N columns. You have to print the total number of rectangles which can be formed using the rows and columns of this grid. In simple words, print the number of unique rectangles in the grid.

For example:

Consider the grid shown below. The dark black boundary encloses a grid of dimension 3x4.

The green colour represents rectangles of dimension 1x1. 
The brown colour represents the rectangles of dimension 1x2.
The blue colour represents the rectangles of dimension 2x2.
The red colour represents the rectangles of dimension 3x3.
The yellow colour represents the rectangles of dimension 3x1.
There can be many different other possibilities as well. You need to print the total number of all such rectangles. 

Note:

Two rectangles are said to be unique if atleast one of their 4 sides is non-overlapping.

You are given a list of rectangles where each rectangle is represented by an array of four integers (i.e. Rectangle[i]=[x1, y1, x2, y2], where x1, y1 represents the bottom left point of the rectangle and x2.y2 represents the top right point of the rectangle, you have to find the total area covered by all the rectangles in the plane.

Example :

Rectangles = [[0, 0, 2, 2], [1, 0, 2, 3],[1, 0, 3, 1]], 

For the given three rectangles, you can observe that the first rectangle occupies an area of 4 units and the second rectangle has an area of 3 units, but we have to keep one thing also in mind that they have an area of 3 units common overlapping among them, so we cannot include it again, so the final area which comes out for all the rectangles is 6 units.

Total Area = 6 units

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