  Intermediate RubyIntermediate level challenges and solutions

Course Material

View all Ruby courses
Next Ruby course
• Challenges
• Prime Time

For this challenge you will be determining if an argument is a prime number. 14014 solutions

• Run Length

For this challenge you will determine the Run Length Encoding of a string. 9114 solutions

• Prime Mover

For this challenge you will be returning a certain prime number. 7945 solutions

• Palindrome Two

For this challenge you will be determining if a string is a palindrome. 8016 solutions

• Division

For this challenge you will determine the Greatest Common Factor between two numbers. 7017 solutions

• String Scramble

For this challenge you will determine if string 1 can be rearranged into string 2. 7985 solutions

• Arith Geo II

For this challenge you will determine if numbers within an array follow an arithmetic or geometric sequence. 5270 solutions

For this challenge you will determine if numbers in an array can add up to a certain number in the array. 5083 solutions

• Binary Converter

For this challenge you will be converting a number from binary to decimal. 4894 solutions

• Letter Count

For this challenge you will determine which word has the greatest number of repeated letters. 5119 solutions

• Caesar Cipher

For this challenge you will transform a string using the Caesar Cipher. 5751 solutions

• Simple Mode

For this challenge you will determine the mode, the number that appears most frequently, in an array. 5287 solutions

• Consecutive

For this challenge you will determine how to order an array of numbers consecutively. 4337 solutions

• Formatted Division

For this challenge you will divide two numbers and print them in a certain format. 4010 solutions

• Counting Minutes

For this challenge you will return the total number of minutes between two times. 3015 solutions

• Permutation Step

For this challenge you will determine the next greatest number using the same numbers of a given argument. 3884 solutions

• Prime Checker

For this challenge you will determine if you can arrange a number to be a prime number. 2736 solutions

• Dash Insert II

For this challenge you will be manipulating a string using dashes (-). 5155 solutions

• Swap II

For this challenge you will be manipulating numbers in a string based on the characters. 3296 solutions

• Number Search

For this challenge you will traverse a string searching for all the numbers and then you will add them up. 3588 solutions

• Triple Double

For this challenge you will determine if there is a number that appears consecutively in both arguments. 3300 solutions

• Bracket Matcher

For this challenge you will determine if the brackets in a string are correctly matched up. 3142 solutions

• String Reduction

For this challenge you will manipulate a string of characters using a simple reduction method. 2763 solutions

• ThreeFive Multiples

For this challenge you will be determining the multiples of a specific number. 3013 solutions

• Binary Search Tree LCA

For this challenge you will attempt to find the lowest common ancestor of a binary search tree. 493 solutions

• Coin Determiner

For this challenge you will be determining the smallest combination of coins for a given output 2703 solutions

• Fibonacci Checker

For this challenge you will be determining whether a number is part of the Fibonacci sequence. 2925 solutions

• Multiple Brackets

For this challenge you will determine if all the brackets in a string are correctly matched up. 2477 solutions

• Most Free Time

For this challenge you will determine what period of the day gives the most free time. 1657 solutions

• Overlapping Rectangles

For this challenge you will be determining the areas of rectangles. 1719 solutions

• Look Say Sequence

For this challenge you will determine the next number in a sequence. 1561 solutions

• Distinct List

For this challenge you will remove duplicate elements from an array. 2730 solutions

• Number Encoding

For this challenge you will encode a given string following a specific rule. 1779 solutions

• Stock Picker

For this challenge you will determine the maximum profit that can be made in a range of stock prices. 1098 solutions

• Max Subarray

For this challenge you will determine the largest sum subarray. 1241 solutions

• Missing Digit

For this challenge you will determine what the variable is in a mathematical equation. 760 solutions

• K Unique Characters

For this challenge you will be searching a string for a particular substring. 1056 solutions

• Bitmap Holes

For this challenge you will be searching within a 2D matrix. 425 solutions

• Symmetric Tree

For this challenge you will traverse a binary tree and determine if it is symmetric. 436 solutions

• Binary Tree LCA

For this challenge you will attempt to find the lowest common ancestor of a binary tree. 355 solutions

• LRU Cache

For this challenge you will determine the order of elements within a simulated cache. 1164 solutions

• Tree Constructor

For this challenge you will determine if an array of integer pairs can form a binary tree properly. 555 solutions

• Array Min Jumps

For this challenge you will determine how quickly you can reach the end of an array. 300 solutions

• Nearest Smaller Values

For this challenge you will determine the nearest smaller value for each number in an array. 624 solutions

• Matrix Spiral

For this challenge you will print a 2D matrix in spiral order. 640 solutions

• Word Split

For this challenge you will attempt to split a long string of characters into actual words. 1211 solutions

• Pair Searching

For this challenge you will determine how to multiply a number to find a duplicate pair. 183 solutions

• Boggle Solver

For this challenge you will attempt to find words in a matrix of letters. 177 solutions

• HTML Elements

For this challenge you will determine whether HTML elements are nested correctly. 532 solutions

• Missing Digit II

For this challenge you will determine what the variables are in a mathematical equation. 207 solutions

• Palindromic Substring

For this challenge you will be finding the longest palindromic substring. 551 solutions

• Trapping Water

For this challenge you will determine the largest amount of water you can trap within a boundary. 500 solutions

• Matrix Path

For this challenge you will determine if a path exists in a boolean matrix. 351 solutions

• Seating Students

For this challenge you will determine how many different ways students can sit next to each other. 834 solutions

• Longest Matrix Path

For this challenge you will be searching for the longest path in a 2D matrix. 104 solutions

• Min Window Substring

For this challenge you will be searching for the optimal substring of k characters. 1336 solutions

• Matrix Chains

For this challenge you will determine the best order to multiply matrices. 95 solutions

• Histogram Area

For this challenge you will determine the largest area under a histogram. 369 solutions

• Matching Characters

For this challenge you will be determining the largest number of unique characters between two letters. 623 solutions

• Ternary Converter

For this challenge you will be converting a decimal number into ternary. 124 solutions

• Linear Congruence

For this challenge you will be solving a linear congruence equation. 75 solutions

• Formatted Number

For this challenge you will be determining if a string is a valid number. 342 solutions

• Largest Row Column

For this challenge you will be finding the largest sum of three digits in a matrix. 111 solutions

• Eight Queens

This challenge will require knowledge of chess pieces and their movements. 3622 solutions

• Three Points

For this challenge you will be plotting a line on a Cartesian grid. 254 solutions

• Character Removal

For this challenge you will attempt to modify a word and then find it within a dictionary. 228 solutions

For this challenge you will be determining if a string is a valid password. 707 solutions

• Preorder Traversal

For this challenge you will be traversing a binary tree. 224 solutions

• String Zigzag

For this challenge you will be printing a string in a particular zig-zag format. 140 solutions

• Off Binary

For this challenge you will be determining the correct binary number. 164 solutions

• Longest Consecutive

For this challenge you will compute the length of the longest consecutive subsequence. 509 solutions

• String Expression

For this challenge you will convert a string of written numbers to an actual number. 191 solutions

• Charlie the Dog

For this challenge you will be helping a dog collect all the food in a grid. 271 solutions

• Plus Minus

For this challenge you will need to determine how to add or subtract numbers to end up with zero. 739 solutions

• Primes

For this challenge you will be determining if an argument is a prime number. 167 solutions

• String Calculate

For this challenge you will be evaluating a mathematical expression within a string. 233 solutions