Sign up
Log in
Home
Language tracks
LFE track
Exercises
Exercises on the LFE track
Join the LFE Track
31 exercises to help you master LFE
easy
Hello World
The classical introductory exercise. Just say "Hello, World!"
strings
easy
Leap
Given a year, report if it is a leap year.
misc
easy
RNA Transcription
Given a DNA strand, return its RNA Complement Transcription.
misc
easy
Bob
Bob is a lackadaisical teenager. In conversation, his responses are very limited.
misc
easy
Sum Of Multiples
Given a number, find the sum of all the multiples of particular numbers up to but not including that number.
math
easy
Strain
Implement the `keep` and `discard` operation on collections. Given a collection and a predicate on the collection's elements, `keep` returns a new collection containing those elements where the predicate is true, while `discard` returns a new collection containing those elements where the predicate is false.
misc
easy
Hamming
Calculate the Hamming difference between two DNA strands.
misc
easy
Space Age
Given an age in seconds, calculate how old someone is in terms of a given planet's solar years.
misc
easy
Grains
Calculate the number of grains of wheat on a chessboard given that the number on each square doubles.
misc
easy
Anagram
Given a word and a list of possible anagrams, select the correct sublist.
misc
easy
Nucleotide Count
Given a DNA string, compute how many times each nucleotide occurs in the string.
misc
easy
Atbash Cipher
Create an implementation of the atbash cipher, an ancient encryption system created in the Middle East.
misc
easy
Phone Number
Clean up user-entered phone numbers so that they can be sent SMS messages.
misc
easy
Robot Simulator
Write a robot simulator.
misc
easy
Grade School
Given students' names along with the grade that they are in, create a roster for the school
misc
easy
Binary
Convert a binary number, represented as a string (e.g. '101010'), to its decimal equivalent using first principles
math
easy
Word Count
Given a phrase, count the occurrences of each word in that phrase.
misc
easy
Circular Buffer
A data structure that uses a single, fixed-size buffer as if it were connected end-to-end.
misc
easy
ETL
We are going to do the `Transform` step of an Extract-Transform-Load.
misc
easy
Clock
Implement a clock that handles times without dates.
misc
easy
Gigasecond
Given a moment, determine the moment that would be after a gigasecond has passed.
misc
easy
Beer Song
Produce the lyrics to that beloved classic, that field-trip favorite: 99 Bottles of Beer on the Wall.
misc
easy
Difference Of Squares
Find the difference between the square of the sum and the sum of the squares of the first N natural numbers.
math
easy
Allergies
Given a person's allergy score, determine whether or not they're allergic to a given item, and their full list of allergies.
misc
easy
Bank Account
Simulate a bank account supporting opening/closing, withdraws, and deposits of money. Watch out for concurrent transactions!
misc
easy
Luhn
Given a number determine whether or not it is valid per the Luhn formula.
misc
easy
Series
Given a string of digits, output all the contiguous substrings of length `n` in that string.
misc
easy
Trinary
Convert a trinary number, represented as a string (e.g. '102012'), to its decimal equivalent using first principles.
math
easy
Largest Series Product
Given a string of digits, calculate the largest product for a contiguous substring of digits of length n.
math
easy
Meetup
Calculate the date of meetups.
misc
easy
Parallel Letter Frequency
Count the frequency of letters in texts using parallel computation.
misc