Hackerrank

Flatland is a country with a number of cities, some of which have space stations. Cities are numbered consecutively and each has a road of  length connecting it to the next city. It is not a circular route, so the first city doesn't connect with the last city.

Emma is playing a new mobile game that starts with consecutively numbered clouds. Some of the clouds are thunderheads and others are cumulus. She can jump on any cumulus cloud having a number that is equal to the number of the current cloud plus  or . She must avoid the thunderheads.

Lilah has a string, , of lowercase English letters that she repeated infinitely many times. Given an integer, , find and print the number of letter a's in the first  letters of Lilah's infinite string. For example, if the string  and , the substring we consider is , the first

Check Tutorial tab to know how to to solve. You are given a string  consisting only of digits 0-9, commas ,, and dots . Your task is to complete the regex_pattern defined below, which will be used to re.split() all of the , and . symbols in . It’s guaranteed that every

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. Laura plants a Utopian Tree sapling with a height of 1 meter at the onset of spring. How tall will her tree be after  growth

ABCXYZ company has up to  employees. The company decides to create a unique identification number (UID) for each of its employees. The company has assigned you the task of validating all the randomly generated UIDs. A valid UID must follow the rules below: * It must contain at least  uppercase English

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

A Discrete Mathematics professor has a class of students. Frustrated with their lack of discipline, he 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

Given an array of integers, find and print the maximum number of integers you can select from the array such that the absolute difference between any two of the chosen integers is less than or equal to . For example, if your array is , you can create two subarrays meeting the

Lexicographical order is often known as alphabetical order when dealing with strings. A string is greater than another string if it comes later in a lexicographically sorted list. Given a word, create a new word by swapping some or all of its characters. This new word must meet two criteria: