Viral Advertising | Python Solution | HackerRank

 HackerLand Enterprise is adopting a new viral advertising strategy. When they launch a new product, they advertise it to exactly  people on social media.

On the first day, half of those  people (i.e., ) like the advertisement and each shares it with  of their friends. At the beginning of the second day,  people receive the advertisement.

Each day,  of the recipients like the advertisement and will share it with  friends on the following day. Assuming nobody receives the advertisement twice, determine how many people have liked the ad by the end of a given day, beginning with launch day as day .

Beautiful Days at the Movies | Python Solution | HackerRank

 Lily likes to play games with integers. She has created a new game where she determines the difference between a number and its reverse. For instance, given the number , its reverse is . Their difference is . The number  reversed is , and their difference is .

She decides to apply her game to decision making. She will look at a numbered range of days and will only go to a movie on a beautiful day.

Given a range of numbered days,  and a number , determine the number of days in the range that are beautiful. Beautiful numbers are defined as numbers where  is evenly divisible by . If a day's value is a beautiful number, it is a beautiful day. Return the number of beautiful days in the range.

Angry Professor | Python Solution | HackerRank

 A Discrete Mathematics professor has a class of students. Frustrated with their lack of discipline, the professor decides to cancel class if fewer than some number of students are present when class starts. Arrival times go from on time () to arrived late ().

Given the arrival time of each student and a threshhold number of attendees, determine if the class is cancelled.

Example

The first  students arrived on. The last  were late. The threshold is  students, so class will go on. Return YES.

Note: Non-positive arrival times () indicate the student arrived early or on time; positive arrival times () indicate the student arrived  minutes late.

Utopian Tree | Python Solution | HackerRank

 The Utopian Tree goes through 2 cycles of growth every year. Each spring, it doubles in height. Each summer, its height increases by 1 meter.

A Utopian Tree sapling with a height of 1 meter is planted at the onset of spring. How tall will the tree be after  growth cycles?

For example, if the number of growth cycles is , the calculations are as follows:

Period  Height
0          1
1          2
2          3
3          6
4          7
5          14

Designer PDF Viewer | Python Solution | HackerRank

 When a contiguous block of text is selected in a PDF viewer, the selection is highlighted with a blue rectangle. In this PDF viewer, each word is highlighted independently. For example:

There is a list of  character heights aligned by index to their letters. For example, 'a' is at index  and 'z' is at index . There will also be a string. Using the letter heights given, determine the area of the rectangle highlight in  assuming all letters are  wide.