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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...

2 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...

2 years ago

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Alphabetize by last name
Given a list of names in a cell array, sort the list by the last name. So if list = {'Barney Google','Snuffy Smith','Dagwood ...

2 years ago

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Find state names that start with the letter N
Given a list of US states, remove all the states that start with the letter N. If s1 = 'Alabama Montana Nebraska Vermont Ne...

2 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...

2 years ago

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Remove the polynomials that have positive real elements of their roots.
The characteristic equation for a dynamic system is a polynomial whose roots indicate its behavior. If any of the roots of the p...

2 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...

2 years ago

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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...

2 years 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...

2 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...

2 years 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 ...

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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, ...

2 years ago

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The Goldbach Conjecture
The Goldbach conjecture asserts that every even integer greater than 2 can be expressed as the sum of two primes. Given the eve...

2 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...

2 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...

2 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...

2 years 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...

2 years 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...

2 years 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...

2 years ago

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Return a list sorted by number of occurrences
Given a vector x, return a vector y of the unique values in x sorted by the number of occurrences in x. Ties are resolved by a ...

2 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 = 2...

2 years 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...

2 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...

2 years 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...

2 years ago

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Replace NaNs with the number that appears to its left in the row.
Replace NaNs with the number that appears to its left in the row. If there are more than one consecutive NaNs, they should all ...

2 years ago

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Remove any row in which a NaN appears
Given the matrix A, return B in which all the rows that have one or more <http://www.mathworks.com/help/techdoc/ref/nan.html NaN...

2 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 ...

2 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...

2 years 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...

2 years 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...

2 years ago