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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 ...

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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Sum of diagonal of a square matrix
If x = [1 2 4; 3 4 5; 5 6 7] then y should be the sum of the diagonals of the matrix y = 1 + 4 + 7 = 12

13 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...

13 years ago

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Back to basics 22 - Rotate a matrix
Covering some basic topics I haven't seen elsewhere on Cody. Rotate the input matrix 90 degrees counterclockwise (e.g. [1 2; ...

13 years ago

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So many choices
For inputs _n_ and _k_ (in that order), output the number of ways that k objects can be chosen from amongst n distinct objects. ...

13 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...

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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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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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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Tell me the slope
Tell me the slope, given a vector with horizontal run first and vertical rise next. Example input: x = [10 2];

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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Magic!
Check whether the input matrix is a normal magic square: <http://en.wikipedia.org/wiki/Magic_square> Output the logical va...

13 years ago

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Is my wife right? Now with even more wrong husband
Again, as in "Is my wife right?" ( <http://www.mathworks.com/matlabcentral/cody/problems/149-is-my-wife-right> ), answer 'yes' r...

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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Scoring for oriented dominoes
Given a list of ordered pairs, and the order they should be placed in a line, find the sum of the absolute values of the differe...

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...

14 years ago

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Swap the input arguments
Write a two-input, two-output function that swaps its two input arguments. For example: [q,r] = swap(5,10) returns q = ...

14 years ago

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Project Euler: Problem 5, Smallest multiple
2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder. What is the smalle...

14 years ago

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Clock Hand Angle 1
Given a time in HH:MM:SS, find the smallest angle (in degrees) between the hour and minute hand

14 years ago

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cos for boss?
a programmer had too much coffee and his boss needs cos(alpha+beta) correctly, especially when alpha or beta or the coffee are c...

14 years ago

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Back to basics 1 - Saving
Covering some basic topics I haven't seen elsewhere on Cody. Given an input variable 'x', save it to disk in a file named 'co...

14 years ago

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Back to basics 6 - Column Vector
Covering some basic topics I haven't seen elsewhere on Cody. Given an input vector, output true or false whether it is a colu...

14 years ago

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No Twins?
Write a function that accepts as input a vector and returns the same vector, but retaining only the first occurrence of an eleme...

14 years ago

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Project Euler: Problem 10, Sum of Primes
The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below the input, N. Thank you <http:/...

14 years ago

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Make one big string out of two smaller strings
If you have two small strings, like 'a' and 'b', return them put together like 'ab'. 'a' and 'b' => 'ab' For extra ...

14 years ago

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Bottles of beer
Given an input number representing the number of bottles of beer on the wall, output how many are left if you take one down and ...

14 years ago

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Arrange Vector in descending order
If x=[0,3,4,2,1] then y=[4,3,2,1,0]

14 years ago

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Who knows the last digit of pi?
There is only one man who knows the last digit of pi, who is that man? Give the name of that man, who, by popular believe, can ...

14 years ago