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"Look and say" sequence
What's the next number in this sequence? * [0] * [1 0] * [1 1 1 0] * [3 1 1 0] * [1 3 2 1 1 0] This a variant on the w...

8 years ago

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Fibonacci-Sum of Squares
Given the Fibonacci sequence defined by the following recursive relation, * F_n = F_(n-1) + F_(n-2) * where F_0 = 0 and F_1 ...

8 years ago

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Return the Fibonacci Sequence
Write a code which returns the Fibonacci Sequence such that the largest value in the sequence is less than the input integer N. ...

8 years ago

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Project Euler: Problem 2, Sum of even Fibonacci
Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 te...

8 years ago

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Project Euler: Problem 6, Natural numbers, squares and sums.
The sum of the squares of the first ten natural numbers is, 1^2 + 2^2 + ... + 10^2 = 385 The square of the sum of the first ...

8 years ago

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Some Assembly Required
The input to this function is a matrix of real numbers. Your job is to assemble the rows of the matrix into one large row that ...

8 years ago

Solved

N-Dimensional Array Slice
Given an N-dimensional array, _A_, an index, _I_, and a dimension, _d_, return the _I_ th elements of _A_ in the _d_ dimension. ...

8 years ago

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Set some matrix elements to zero
First get the maximum of each *row*, and afterwards set all the other elements to zero. For example, this matrix: 1 2 3 ...

8 years ago

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Operate on matrices of unequal, yet similar, size
You may want to add a vector to a matrix, implying that the vector is added to each column of the matrix. Or multiply a 3x4x5 ma...

8 years ago

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Removing rows from a matrix is easy - but what about inserting rows?
Assume A is a 5-by-5 matrix. A([2,4],:) = [] is a quick way to remove rows 2 and 4. Can you find a quick way to insert rows into...

8 years ago

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Most nonzero elements in row
Given the matrix a, return the index r of the row with the most nonzero elements. Assume there will always be exactly one row th...

8 years ago

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Matrix with different incremental runs
Given a vector of positive integers a = [ 3 2 4 ]; create the matrix where the *i* th column contains the vector *1:a(i)...

8 years ago

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Alternating sum
Given vector x, calculate the alternating sum y = x(1) - x(2) + x(3) - x(4) + ...

8 years ago

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Sum all integers from 1 to 2^n
Given the number x, y must be the summation of all integers from 1 to 2^x. For instance if x=2 then y must be 1+2+3+4=10.

8 years ago

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Permute diagonal and antidiagonal
Permute diagonal and antidiagonal For example [1 2 3;4 5 6;7 8 9] -> [3 2 1;4 5 6;9 8 7] WITHOUT diag function (and variable n...

8 years ago

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Make an awesome ramp for a tiny motorcycle stuntman
Okay, given a vector, say v=[1 3 6 9 11], turn it into a matrix 'ramp' like so: m=[1 3 6 9 11; 3 6 9 11 0; 6 9 ...

8 years ago

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Remove the air bubbles
Given a matrix a, return a matrix b in which all the zeros have "bubbled" to the top. That is, any zeros in a given column shoul...

8 years ago

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Reverse the elements of an array
Reverse the order of elements in an array: eg: input X = [ 1 2 3 ; 4 5 6 ; 7 8 9 ] o...

8 years ago

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Flip the main diagonal of a matrix
Given a n x n matrix, M, flip its main diagonal. Example: >> M=magic(5); >> flipDiagonal(M) 9 24 1 ...

8 years ago

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Back to basics 23 - Triangular matrix
Covering some basic topics I haven't seen elsewhere on Cody. Given an input matrix, return a matrix with all elements above a...

8 years ago

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Remove NaN ?
input -> matrix (n*m) with at least one element equal to NaN; output -> matrix(p*m), the same matrix where we deleted the enti...

8 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...

8 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 ...

8 years ago

Solved

surrounded matrix
With a given matrix A (size m x n) create a matrix B (size m+2 x n+2) so that the matrix A is surrounded by ones: A = [1 2 ...

8 years 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, ....

8 years ago

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Remove all the consonants
Remove all the consonants in the given phrase. Example: Input s1 = 'Jack and Jill went up the hill'; Output s2 is 'a ...

8 years ago

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Back to basics 21 - Matrix replicating
Covering some basic topics I haven't seen elsewhere on Cody. Given an input matrix, generate an output matrix that consists o...

8 years ago

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Digit concentration in Champernowne's constant
Consider the first 50 digits of Champernowne's constant 0.12345678910111213141516171819202122232425262728293... The...

8 years ago

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"Cody" * 5 == "CodyCodyCodyCodyCody"
*Alice*: What? *"Cody" * 5 == "CodyCodyCodyCodyCody"*? You've gotta be kidding me! *Bob*: No, I am serious! Python supports...

8 years ago

Solved

Acid and water
⚖ ⚖ ⚖ ⚖ ⚖ ⚖ ⚖ ⚖ Assume that there is a 100 liter tank. It is initially fi...

8 years ago