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Find the peak 3n+1 sequence value

A Collatz sequence is the sequence where, for a given number n, the next number in the sequence is either n/2 if the number is e...

3 months ago

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Kaprekar Steps

6174 is the <http://en.wikipedia.org/wiki/6174_%28number%29 Kaprekar constant>. All natural numbers less than 10,000 (except som...

3 months ago

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Find common elements in matrix rows

Given a matrix, find all elements that exist in every row. For example, given A = 1 2 3 5 9 2 5 9 3 2 5 9 ...

3 months ago

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Find the two-word state names

Given a list of states, remove all the states that have two-word names. If s1 = 'Alabama Montana North Carolina Vermont N...

3 months ago

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Word Counting and Indexing

You are given a list of strings, each being a list of words divided by spaces. Break the strings into words, then return a maste...

3 months ago

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The Goldbach Conjecture, Part 2

The <http://en.wikipedia.org/wiki/Goldbach's_conjecture Goldbach conjecture> asserts that every even integer greater than 2 can ...

3 months ago

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Encode Roman Numerals

Create a function taking a non-negative integer as its parameter and returning a string containing the Roman Numeral representat...

3 months ago

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Elapsed Time

Given two date strings d1 and d2 of the form yyyy/mm/dd HH:MM:SS (assume hours HH is in 24 hour mode), determine how much time, ...

3 months ago

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Find state names that end with the letter A

Given a list of US states, remove all the states that end with the letter A. Example: Input s1 = 'Alabama Montana Nebras...

3 months ago

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The Goldbach Conjecture

The <http://en.wikipedia.org/wiki/Goldbach's_conjecture Goldbach conjecture> asserts that every even integer greater than 2 can ...

3 months ago

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Pattern matching

Given a matrix, m-by-n, find all the rows that have the same "increase, decrease, or stay same" pattern going across the columns...

3 months ago

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Tic Tac Toe FTW

Given a tic tac toe board: * 1 represents X * 0 represents empty. * -1 represents O It is X's move. If there is an imme...

3 months ago

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Summing Digits within Text

Given a string with text and digits, add all the numbers together. Examples: Input str = '4 and 20 blackbirds baked in a...

3 months ago

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Scrabble Scores

Given a word, determine its score in <http://en.wikipedia.org/wiki/Scrabble Scrabble>. The input string will always be provi...

3 months ago

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Counting Sequence

Given a vector x, find the "counting sequence" y. A counting sequence is formed by "counting" the entries in a given sequence...

3 months ago

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Maximum running product for a string of numbers

Given a string s representing a list of numbers, find the five consecutive numbers that multiply to form the largest number. Spe...

3 months ago

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Duplicates

Write a function that accepts a cell array of strings and returns another cell array of strings *with only the duplicates* retai...

3 months ago

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What is the next step in Conway's Life?

Given a matrix A that represents the state of <http://en.wikipedia.org/wiki/Conway's_Game_of_Life Conway's game of Life> at one ...

3 months ago

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Find the two most distant points

Given a collection of points, return the indices of the rows that contain the two points most distant from one another. The inpu...

3 months ago

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QWERTY coordinates

Given a lowercase letter or a digit as input, return the row where that letter appears on a standard U.S. QWERTY keyboard and it...

3 months ago

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Sums with Excluded Digits

Add all the integers from 1 to n in which the digit m does not appear. m will always be a single digit integer from 0 to 9. no...

3 months ago

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Making change

Given an amount of currency, return a vector of this form: [100 50 20 10 5 2 1 0.5 0.25 0.1 0.05 0.01] Example: Input a = ...

3 months ago

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Extract leading non-zero digit

<http://en.wikipedia.org/wiki/Benford%27s_law Benford's Law> states that the distribution of leading digits is not random. This...

3 months ago

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Which doors are open?

There are n doors in an alley. Initially they are all shut. You have been tasked to go down the alley n times, and open/shut the...

3 months ago

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Make a Palindrome Number

Some numbers like 323 are palindromes. Other numbers like 124 are not. But look what happens when we add that number to a revers...

3 months ago

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Subset Sum

Given a vector v of integers and an integer n, return the the indices of v (as a row vector in ascending order) that sum to n. I...

3 months ago

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Pascal's Triangle

Given an integer n >= 0, generate the length n+1 row vector representing the n-th row of <http://en.wikipedia.org/wiki/Pascals_t...

3 months ago

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Find the alphabetic word product

If the input string s is a word like 'hello', then the output word product p is a number based on the correspondence a=1, b=2, ....

3 months ago

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Cell joiner

You are given a cell array of strings and a string delimiter. You need to produce one string which is composed of each string fr...

3 months ago

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Reverse Run-Length Encoder

Given a "counting sequence" vector x, construct the original sequence y. A counting sequence is formed by "counting" the entrie...

3 months ago