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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...

13 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...

13 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...

13 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...

13 years 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...

13 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...

13 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...

13 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 <http://en.wikipedia.org/wiki/Keyboa...

13 years ago

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Function Iterator
Given a handle fh to a function which takes a scalar input and returns a scalar output and an integer n >= 1, return a handle f...

13 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 ...

13 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...

13 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...

13 years ago

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Trimming Spaces
Given a string, remove all leading and trailing spaces (where space is defined as ASCII 32). Input a = ' singular value deco...

13 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...

13 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...

13 years ago

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De-dupe
Remove all the redundant elements in a vector, but keep the first occurrence of each value in its original location. So if a =...

13 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 ...

13 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 = ...

13 years 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, ...

13 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...

13 years ago

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Find the longest sequence of 1's in a binary sequence.
Given a string such as s = '011110010000000100010111' find the length of the longest string of consecutive 1's. In this examp...

13 years ago

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How long is the longest prime diagonal?
Stanislaw Ulam once observed that if the counting numbers are <http://en.wikipedia.org/wiki/Ulam_spiral arranged in a spiral>, t...

13 years ago

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Find the biggest empty box
You are given a matrix that contains only ones and zeros. Think of the ones as columns in an otherwise empty floor plan. You wan...

13 years ago

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Solitaire Cipher
Implement the <http://en.wikipedia.org/wiki/Solitaire_(cipher) solitaire cipher>. Since this is from Wikipedia, I am capturin...

13 years ago

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Spot the outlier
All points except for one lie on a line. Which one is the outlier? Example: You are given a list of x-y pairs in a column ...

13 years ago

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Make a run-length companion vector
Given a vector x, return a vector r that indicates the run length of any value in x. Each element in r shows how many times the ...

13 years ago

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Flag largest magnitude swings as they occur
You have a phenomenon that produces strictly positive or negative results. delta = [1 -3 4 2 -1 6 -2 -7]; Marching thr...

13 years ago

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How many trades represent all the profit?
Given a list of results from trades made: [1 3 -4 2 -1 2 3] We can add them up to see this series of trades made a profit ...

13 years ago

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Given a window, how many subsets of a vector sum positive
Given a vector: [1 0 -1 3 2 -3 1] and a window of 2, A sliding window would find: 1 + 0 = 1 0 - 1 = -1 ...

13 years ago

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Implement simple rotation cypher
If given a letter from the set: [abc...xyz] and a shift, implement a shift cypher. Example: 'abc' with a shi...

13 years ago