Hackerrank

John has collected various rocks. Each rock has various minerals embeded in it. Each type of mineral is designated by a lowercase letter in the range . There may be multiple occurrences of a mineral in a rock. A mineral is called a gemstone if it occurs at least once in

Steve has a string of lowercase characters in range ascii[‘a’..’z’]. He wants to reduce the string to its shortest length by doing a series of operations. In each operation he selects a pair of adjacent lowercase letters that match, and he deletes them. For instance, the string aab

In this challenge, you will determine whether a string is funny or not. To determine whether a string is funny, create a copy of the string in reverse e.g. . Iterating through each string, compare the absolute difference in the ascii values of the characters at positions 0 and 1,

Roy wanted to increase his typing speed for programming contests. His friend suggested that he type the sentence "The quick brown fox jumps over the lazy dog" repeatedly. This sentence is known as a pangram because it contains every letter of the alphabet. After typing the sentence several

We say that a string contains the word hackerrank if a subsequence of its characters spell the word hackerrank. For example, if string  it does contain hackerrank, but  does not. In the second case, the second r is missing. If we reorder the first string as , it no longer contains

Sami's spaceship crashed on Mars! She sends a series of SOS messages to Earth for help. Letters in some of the SOS messages are altered by cosmic radiation during transmission. Given the signal received by Earth as a string, , determine how many letters of Sami's SOS

Alice wrote a sequence of words in CamelCase as a string of letters, , having the following properties: * It is a concatenation of one or more words consisting of English letters. * All letters in the first word are lowercase. * For each of the subsequent words, the first letter is uppercase and

You are given a square map as a matrix of integer strings. Each cell of the map has a value denoting its depth. We will call a cell of the map a cavity if and only if this cell is not on the border of the map and each cell

You are the benevolent ruler of Rankhacker Castle, and today you're distributing bread. Your subjects are in a line, and some of them already have some loaves. Times are hard and your castle's food stocks are dwindling, so you must distribute as few loaves as possible

Lisa just got a new math workbook. A workbook contains exercise problems, grouped into chapters. Lisa believes a problem to be special if its index (within a chapter) is the same as the page number where it's located. The format of Lisa's book is as follows: