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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...

4 years ago

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Counting Money
Add the numbers given in the cell array of strings. The strings represent amounts of money using this notation: $99,999.99. E...

4 years 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 = ...

4 years ago

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Quote Doubler
Given a string s1, find all occurrences of the single quote character and replace them with two occurrences of the single quote ...

4 years ago

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Balanced number
Given a positive integer find whether it is a balanced number. For a balanced number the sum of first half of digits is equal to...

4 years 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...

4 years 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...

4 years ago

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Remove all the words that end with "ain"
Given the string s1, return the string s2 with the target characters removed. For example, given s1 = 'the main event' your ...

4 years ago

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Indexed Probability Table
This question was inspired by a Stack Overflow question forwarded to me by Matt Simoneau. Given a vector x, make an indexed pro...

4 years 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...

4 years 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...

4 years 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...

4 years ago

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Read a column of numbers and interpolate missing data
Given an input cell array of strings s, pick out the second column and turn it into a row vector of data. Missing data will be i...

4 years ago

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Implement a ROT13 cipher
Replace each character in string s1 with the character that is shifted 13 positions from it (wrap back to the beginning if neces...

4 years 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...

4 years 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...

4 years ago

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Find relatively common elements in matrix rows
You want to find all elements that exist in greater than 50% of the rows in the matrix. For example, given A = 1 2 3 5 ...

4 years ago

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Get the area codes from a list of phone numbers
Given a string of text with phone numbers in it, return a unique'd cell array of strings that are the area codes. s = '508-647...

4 years ago

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Find all elements less than 0 or greater than 10 and replace them with NaN
Given an input vector x, find all elements of x less than 0 or greater than 10 and replace them with NaN. Example: Input ...

4 years ago

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It dseon't mettar waht oedrr the lrettes in a wrod are.
An internet meme from 2003 (read more here) asserted that readers are relatively insensitive to letter order in words, so long a...

4 years ago

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Find the palindrome
Given the string a, find the longest palindromic sub-string b. So when a = 'xkayakyy'; you should return b = 'kayak';

4 years ago

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Connect Four Win Checker
<http://en.wikipedia.org/wiki/Connect_Four Connect Four> is a game where you try to get four pieces in a row. For this problem, ...

4 years ago

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Longest Divisor Run
Given the vector a, find the longest run of consecutive numbers that can be evenly divided by the same number d where d > 1. ...

4 years ago

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Knight's Tour Checker
Given a matrix a, determine whether or not a legal <http://en.wikipedia.org/wiki/Knight's_tour knight's tour> is present. The kn...

4 years ago

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DNA N-Gram Distribution
Given a string s and a number n, find the most frequently occurring n-gram in the string, where the n-grams can begin at any poi...

4 years ago

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Interpolator
You have a two vectors, a and b. They are monotonic and the same length. Given a value, va, where va is between a(1) and a(end...

4 years ago

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Determine if input is odd
Given the input n, return true if n is odd or false if n is even.

4 years ago

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Mandelbrot Numbers
The <http://en.wikipedia.org/wiki/Mandelbrot_set Mandelbrot Set> is built around a simple iterative equation. z(1) = c z...

4 years 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...

4 years ago

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Given two arrays, find the maximum overlap
Given two arrays s1 and s2, create a new array s3 which is as short as possible and contains both arrays. If s1 = [1 2 3 4 5]...

4 years ago