| # | Name | Description | Solution | Test |
|---|---|---|---|---|
| 1 | Fizz Buzz | A simple game involving divisibility tests. | ✅💾 | ✅💾 |
| 3 | Prime Palindrome | Biggest prime palindrome < 1000. | ✅💾 | ✅💾 |
| 4 | Sum of Primes | Sum of first 1000 primes. | ✅💾 | ✅💾 |
| 8 | Reverse words | Reversing an input sequence of words. | ✅💾 | ✅💾 |
| 18 | Multiples of a Number | Multiples of a number greater than another number. | ✅💾 | ✅💾 |
| 19 | Bit Positions | Bits in position x,y are same or different. | ✅💾 | ✅💾 |
| 20 | Lowercase | Lowercase text | ✅💾 | ✅💾 |
| 21 | Sum of Digits | Sum of digits comprising a number | ✅💾 | ✅💾 |
| 22 | Fibonacci Series | Print out the nth fibonacci number | ✅💾 | ✅💾 |
| 23 | Multiplication Tables | Print out the grade school multiplication table upto 12*12 | ✅💾 | ✅💾 |
| 24 | Sum of Integers from File | Print the sum of integers read from a file. | ✅💾 | ✅💾 |
| 25 | Odd Numbers | Print the odd numbers from 1 to 99. | ✅💾 | ✅💾 |
| 26 | File Size | Print the file size in bytes. | ✅💾 | ✅💾 |
| 29 | Unique Elements | Extract unique list from a sorted list of numbers. | ✅💾 | ✅💾 |
| 30 | Set Intersection | Print the intersection of two sets of numbers. | ✅💾 | ✅💾 |
| 31 | Rightmost Char | Print the position of the rightmost occurrence of a char. | ✅💾 | ✅💾 |
| 39 | Happy Numbers | Determine if a number is a happy number or not | ✅💾 | ✅💾 |
| 40 | Self Describing Numbers | Determine if a number is a self-describing number or not | ✅💾 | ✅💾 |
| 62 | N Mod M | Determine the modulus (without the modulus operator). | ✅💾 | ✅💾 |
| 67 | Hex to Decimal | Convert a hex number to it's decimal equivalent. | ✅💾 | ✅💾 |
| 82 | Armstrong Numbers | Determine if a number is an armstrong number. | ✅💾 | ✅💾 |
| 83 | Beautiful Strings | Facebook Hacker Cup 2013 problem. | ✅💾 | ✅💾 |
| 87 | Query Board | Set and get values from a matrix using tiny DSL | ✅💾 | ✅💾 |
| 91 | Simple Sorting | Sort several numbers | ✅💾 | ✅💾 |
| 92 | Penultimate Word | Find the next-to-last word | ✅💾 | ✅💾 |
| 93 | Capitalize Words | Capitalize words in a sentence | ✅💾 | ✅💾 |
| 96 | Swap Case | Swap case in a string | ✅💾 | ✅💾 |
| 97 | Find a Writer | Find a famous writer in a string | ✅💾 | ✅💾 |
| 99 | Calculate Distance | Calculate a distance between two points | ✅💾 | ✅💾 |
| 100 | Even Numbers | Determine if a number is even or not | ✅💾 | ✅💾 |
| 102 | JSON menu IDs | Calculate IDs in JSON menu | ✅💾 | ✅💾 |
| 103 | Lowest Unique Number | Find the lowest unique number in a set | ✅💾 | ✅💾 |
| 104 | Word to Digit | Substitute words to digits | ✅💾 | ✅💾 |
| 106 | Roman Numerals | Convert a cardinal number to a Roman numeral | ✅💾 | ✅💾 |
| 107 | Shortest Repetition | Find the shortest repetition in a string | ✅💾 | ✅💾 |
| 111 | Longest Word | Get the longest word in a sentence | ✅💾 | ✅💾 |
| 112 | Swap Elements | Swap elements in a list | ✅💾 | ✅💾 |
| 113 | Multiply Lists | Multiply elements in 2 lists | ✅💾 | ✅💾 |
| 115 | Mixed Content | Separate words with digits | ✅💾 | ✅💾 |
| 116 | Morse Code | Decode Morse code | ✅💾 | ✅💾 |
| 122 | Hidden Digits | Try to look behind the scenes | ✅💾 | ✅💾 |
| 124 | Road Trip | Do not be left without petrol | ✅💾 | ✅💾 |
| 128 | Compressed Sequence | Write a program that compresses a sequence of numbers | ✅💾 | ✅💾 |
| 131 | Split The Number | Evaluate the number according to the pattern | ✅💾 | ✅💾 |
| 132 | The Major Element | Find the major element in a sequence | ✅💾 | ✅💾 |
| 136 | Racing Chars | Explore a race track avoiding crashes | ✅💾 | ✅💾 |
| 139 | Working experience | Retrieve an actual value | ✅💾 | ✅💾 |
| 140 | Data Recovery | Reconstruct a sentence using hints | ✅💾 | ✅💾 |
| 147 | Lettercase Percentage Ratio | Find the percentage ratio. | ✅💾 | ✅💾 |
| 149 | Juggling With Zeros | Convert a zero-based number into integer. | ✅💾 | ✅💾 |
| 152 | Age distribution | Print out where the person is. | ✅💾 | ✅💾 |
| 156 | Roller Coaster | Turn the text into RoLlErCoAsTeR case. | ✅💾 | ✅💾 |
| 160 | Nice angles | Convert angle values to sexagesimal format. | ✅💾 | ✅💾 |
| 163 | Big Digits | Print out magnified digits using pseudographics. | ✅💾 | ✅💾 |
| 166 | Delta Time | Find the time difference. | ✅💾 | ✅💾 |
| 167 | Read More | Limit the length of the text. | ✅💾 | ✅💾 |
| 173 | Without Repetitions | Delete characters that are consistently repeated. | ✅💾 | ✅💾 |
| 174 | Slang Flavor | Add some slang to the text. | ✅💾 | ✅💾 |
| 179 | Matrix Rotation | Rotate a 2D matrix 90 degrees clockwise. | ✅💾 | ✅💾 |
| 180 | Knight Moves | Find positions for the next move of the knight. | ✅💾 | ✅💾 |
| 183 | Details | Determine how many cells will be shifted detail. | ✅💾 | ✅💾 |
| 186 | Max Range Sum | Determine max sum at the range. | ✅💾 | ✅💾 |
| 189 | Minimum Distance | Find a point with the smallest sum of distances to every given point. | ✅💾 | ✅💾 |
| 192 | Compare Points | Given two (x, y) points A and B, determine which cardinal direction B is from A. | ✅💾 | ✅💾 |
| 196 | Swap Numbers | Swap numbers surrounding a word | ✅💾 | ✅💾 |
| 199 | String mask | Change case letters by mask | ✅💾 | ✅💾 |
| 202 | Stepwise word | Print the longest word in a stepwise manner | ✅💾 | ✅💾 |
| 203 | Strings and arrows | Print the number of arrows in a string | ✅💾 | ✅💾 |
| 205 | Clean up the words | Print the words separated by spaces | ✅💾 | ✅💾 |
| 208 | Find the highest score | Find the highest rate in the table | ✅💾 | ✅💾 |
| 211 | Chardonnay or Cabernet | Guess a wine name. | ✅💾 | ✅💾 |
| 214 | Time to eat | Sort timestamps in the right order. | ✅💾 | ✅💾 |
| 217 | One zero, two zeros... | Count zeros in a binary system. | ✅💾 | ✅💾 |
| 220 | Trick or Treat | Count all candies. | ✅💾 | ✅💾 |
| 222 | Black card | Find the winner. | ✅💾 | ✅💾 |
| 225 | Testing | Wanna try to be a tester? | ✅💾 | ✅💾 |
| 227 | Real fake | Check credit card numbers. | ✅💾 | ✅💾 |
| 230 | Football | Find countries that are football fans. | ✅💾 | ✅💾 |
| 232 | Not so clever | Simplicity is not always good. | ✅💾 | ✅💾 |
| 235 | Simple or trump | Check which card is higher. | ✅💾 | ✅💾 |
| 237 | Panacea - truth or lie | Check whether the virus was stopped by antivirus. | ✅💾 | ✅💾 |
| 240 | Mersenne prime | Find all Mersenne numbers smaller than n. | ✅💾 | ✅💾 |
| # | Name | Description | Solution | Test |
|---|---|---|---|---|
| 6 | Longest Common Subsequence | LCS between two strings. | ✅💾 | ✅💾 |
| 7 | Prefix expressions | Evaluating a prefix expression. | ✅💾 | ✅💾 |
| 14 | String Permutations | Print out all permutations of a string. | ✅💾 | ✅💾 |
| 28 | String Searching | Determine if substring match exists. | ✅💾 | ✅💾 |
| 36 | Message Decoding | Decode an encoded message | ✅💾 | ✅💾 |
| 38 | String List | Create a new string from constituent alphabets | ✅💾 | ✅💾 |
| 42 | Ugly Numbers | Count the number of expressions that can be created from a number | 💾 | 💾 |
| 44 | Following Integer | Determine the next number in a sequence | ✅💾 | ✅💾 |
| 47 | Palindromic Ranges | Find out a range of palindromic numbers | ✅💾 | ✅💾 |
| 50 | String Substitution | Create a new string by replacing substrings within it | ✅💾 | ✅💾 |
| 51 | Closest Pair | Given a set of points in a two dimensional space, you will have to find the distance between the closest two points. | ✅💾 | ✅💾 |
| 52 | Text Dollar | Print out the text dollar amount of a given quantity | ✅💾 | ✅💾 |
| 56 | Robot Movements | Number of ways a robot can reach its destination | ✅💾 | ✅💾 |
| 57 | Spiral Printing | Print out a 2D array in spiral order | ✅💾 | ✅💾 |
| 59 | Telephone Words | Print out the words corresponding to a telephone number | ✅💾 | ✅💾 |
| 65 | Word Search | Find if a word exists in a grid | ✅💾 | ✅💾 |
| 72 | Minimum Path Sum | Calculate the minimum sum of a path through a matrix. | ✅💾 | ✅💾 |
| 79 | Minesweeper | Find the mines within a M*N matrix. | ✅💾 | ✅💾 |
| 105 | Largest Sub-Matrix | Determine the largest sub-matrix in a matrix | ✅💾 | ✅💾 |
| 108 | Computer Terminal | Print text to terminal with control sequences | ✅💾 | ✅💾 |
| 126 | Play with DNA | Write an algorithm that a finds DNA segment in a given DNA string | 💾 | 💾 |
| 144 | Digit statistics | Find statistics in sequence | ✅💾 | ✅💾 |
| 155 | ASCII Decryption | Decrypt a message. | ✅💾 | ✅💾 |
| 157 | The Labyrinth | Find the shortest way to exit. | ✅💾 | ✅💾 |
| 162 | Too unique | Find and mark the biggest submatrices of unique elements. | ✅💾 | ✅💾 |
| 210 | Brainf*ck | Blow your mind | ✅💾 | ✅💾 |
| 213 | Lakes, not cakes | Count all lakes. | ✅💾 | ✅💾 |
| 216 | Everything or nothing | Check if a code is correct. | ✅💾 | ✅💾 |
| # | Name | Description | Solution | Test |
|---|---|---|---|---|
| 2 | Longest Lines | Finding the 'N' longest lines within a file. | ✅💾 | ✅💾 |
| 5 | Detecting Cycles | Detecting loops within a sequence. | ✅💾 | ✅💾 |
| 9 | Stack Implementation | Implement a stack interface | ✅💾 | ✅💾 |
| 10 | Mth to last element | Determine the Mth to last element | ✅💾 | ✅💾 |
| 11 | Lowest Common Ancestor | Determine the lowest common ancestor within a tree | ✅💾 | ✅💾 |
| 12 | First Non-Repeated Character | Find the first non repeated character in a string. | ✅💾 | ✅💾 |
| 13 | Remove Characters | Delete specific characters from a string. | ✅💾 | ✅💾 |
| 15 | Endianness | Determine the endianness of a system. | ✅💾 | ✅💾 |
| 16 | Number of Ones | Determine the number of one bits in an integer. | ✅💾 | ✅💾 |
| 17 | Sum of integers | Determine the largest sum of contiguous integers in an array. | ✅💾 | ✅💾 |
| 27 | Decimal To Binary | Print the binary representation of a decimal number. | ✅💾 | ✅💾 |
| 32 | Trailing String | Determine if a string 'B' occurs at the end of string 'A' | ✅💾 | ✅💾 |
| 33 | Double Squares | FaceBook Hacker Cup 2011: Output the number of ways to write X as the sum of two squares | ✅💾 | ✅💾 |
| 34 | Number Pairs | Find pairs of numbers in a sorted array whose sum is X | ✅💾 | ✅💾 |
| 35 | Email Validation | Write a regular expression to validate an email address | ✅💾 | ✅💾 |
| 37 | Pangrams | Find the missing alphabets | ✅💾 | ✅💾 |
| 41 | Array Absurdity | Determine if an array contains a duplicated entry | ✅💾 | ✅💾 |
| 43 | Jolly Jumpers | Determine if a sequence of numbers is a Jolly Jumper | ✅💾 | ✅💾 |
| 45 | Reverse and Add | Continually add a number to its reverse to arrive at a palindrome | ✅💾 | ✅💾 |
| 46 | Prime Numbers | Print prime numbers less than N | ✅💾 | ✅💾 |
| 54 | Cash Register | Determine the amount of change to be returned | ✅💾 | ✅💾 |
| 63 | Counting Primes | Count the number of primes between two integers. | ✅💾 | ✅💾 |
| 66 | Pascals Triangle | Print out pascals triangle upto a certain depth. | ✅💾 | ✅💾 |
| 68 | Valid parentheses | Determine if string is a well-formed parentheses | ✅💾 | ✅💾 |
| 70 | Overlapping Rectangles | Determine if two rectangles overlap. | ✅💾 | ✅💾 |
| 71 | Reverse Groups | Reverse elements in a list k items at a time. | ✅💾 | ✅💾 |
| 73 | Decode Numbers | Count the number of ways to decode a string. | ✅💾 | ✅💾 |
| 74 | Minimum Coins | Find the minimum number of coins to arrive at a total. | ✅💾 | ✅💾 |
| 75 | Flavius Josephus | Eliminate every i'th item from a circular list. | ✅💾 | ✅💾 |
| 76 | String Rotation | Find if a string is the rotation of another string. | ✅💾 | ✅💾 |
| 78 | Sudoku | Determine if a grid layout is a valid sudoku solution. | ✅💾 | ✅💾 |
| 80 | URI Comparison | Determine if two URIs match | ✅💾 | ✅💾 |
| 81 | Sum to Zero | Count of ways in which the sum of four numbers is zero | ✅💾 | ✅💾 |
| 84 | Balanced Smileys | Facebook Hacker Cup 2013 problem. | ✅💾 | ✅💾 |
| 89 | Pass Triangle | Lead the way within the triangle | ✅💾 | ✅💾 |
| 94 | Simple Calculator | Create a simple calculator | ✅💾 | ✅💾 |
| 98 | Point in Circle | Define whether a point is in a circle | ✅💾 | ✅💾 |
| 101 | Find a Square | Do 4 points make a square? | ✅💾 | ✅💾 |
| 117 | A Pile of Bricks | Close a hole in a wall | ✅💾 | ✅💾 |
| 119 | Chain Inspection | Try to pass a chain | ✅💾 | ✅💾 |
| 121 | Lost In Translation | Try to become a native speaker | ✅💾 | ✅💾 |
| 125 | Predict the Number | Try to go beyond the limits | ✅💾 | ✅💾 |
| 130 | Sequence Transformation | Transform a binary sequence into a string | ✅💾 | ✅💾 |
| 133 | City Blocks Flyover | Chart the path of a helicopter from above to discover how many city blocks it flew over. | ✅💾 | ✅💾 |
| 135 | Word chain | Find the longest chain of words | ✅💾 | ✅💾 |
| 137 | Seek for an Intruder | Find the IP address of an intruder | ✅💾 | ✅💾 |
| 138 | Car Race | Determine the fastest car | ✅💾 | ✅💾 |
| 143 | The Ministry of Truth | Your task is to help the Big Brother | ✅💾 | ✅💾 |
| 146 | Bats Challenge | Count bats on the wire. | ✅💾 | ✅💾 |
| 148 | Color Code Converter | Determine and convert the color code | ✅💾 | ✅💾 |
| 150 | Roman and Arabic | Calculate aromatic numbers. | ✅💾 | ✅💾 |
| 153 | Locks | Calculate unlocked doors. | ✅💾 | ✅💾 |
| 158 | Interrupted Bubble Sort | Sort a list of elements. Partially. | ✅💾 | ✅💾 |
| 161 | Game of Life | Implement the classical cellular automaton game. | ✅💾 | ✅💾 |
| 165 | Suggest Groups | Help your friends to join groups. | ✅💾 | ✅💾 |
| 169 | Filename Pattern | Filter a list of filenames. | ✅💾 | ✅💾 |
| 170 | Guess the Number | Guess the number in log2(N) steps. | ✅💾 | ✅💾 |
| 172 | Card number validation | Check if bank card numbers are valid. | ✅💾 | ✅💾 |
| 177 | Justify the Text | Align the text to the specified width. | ✅💾 | ✅💾 |
| 178 | Broken LCD | Determine whether a given number can be displayed on the damaged LCD. | ✅💾 | ✅💾 |
| 181 | Gronsfeld cipher | Decipher the message enciphered with the Gronsfeld cipher. | ✅💾 | ✅💾 |
| 184 | Burrows-Wheeler transform | Complete file decompression by inverting BWT. | ✅💾 | ✅💾 |
| 187 | Consecutive Primes | Determine how many ways the numbers can be arranged such that every consecutive pair sums to a prime. | ✅💾 | ✅💾 |
| 190 | Number Operations | Determine if it is possible to produce the number 42 with five cards. | ✅💾 | ✅💾 |
| 193 | Magic Numbers | Print out a list of all the magic numbers in a provided range. | ✅💾 | ✅💾 |
| 194 | Twenty Forty Eight | Implement the 2048 game logic | ✅💾 | ✅💾 |
| 197 | Column Names | Convert integer to excel-style column name | ✅💾 | ✅💾 |
| 200 | Sort matrix columns | Sort matrix columns from lowest to highest numbers | ✅💾 | ✅💾 |
| 206 | Lucky tickets | Count the lucky tickets | ✅💾 | ✅💾 |
| 209 | Black or white | Find the smallest submatrix | ✅💾 | ✅💾 |
| 212 | Robo and Robitta | Count all nuts. | ✅💾 | ✅💾 |
| 215 | Double trouble | Calculate the number of correct variants for messages. | ✅💾 | ✅💾 |
| 218 | Builders team. | Count all squares on the map. | ✅💾 | ✅💾 |
| 221 | Organizational Hierarchy | Recreate the hierarchy tree. | ✅💾 | ✅💾 |
| 223 | Alternative reality | Count all alternative ways. | ✅💾 | ✅💾 |
| 226 | Try to solve it | How good decoder are you? | ✅💾 | ✅💾 |
| 228 | To PI or not to PI | Print a PI number. | ✅💾 | ✅💾 |
| 231 | Meet Cocktail sort | Learn more about cocktail sort algorithm. | ✅💾 | ✅💾 |
| 233 | Meet Comb sort | Learn more about the comb sort algorithm. | ✅💾 | ✅💾 |
| 236 | Beat or bit | Learn more about the Gray code algorithm. | ✅💾 | ✅💾 |
| 238 | Code combinations | Check whether you can make words from the given letters. | ✅💾 | ✅💾 |