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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 ...

2 years ago

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Triangle sequence

A sequence of triangles is constructed in the following way: 1) the first triangle is Pythagoras' 3-4-5 triangle 2) the s...

2 years ago

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Find a Pythagorean triple

Given four different positive numbers, a, b, c and d, provided in increasing order: a < b < c < d, find if any three of them com...

2 years ago

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Is this triangle right-angled?

Given any three positive numbers a, b, c, return true if the triangle with sides a, b and c is right-angled. Otherwise, return f...

2 years ago

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Side of an equilateral triangle

If an equilateral triangle has area A, then what is the length of each of its sides, x? <<http://upload.wikimedia.org/wikipe...

2 years ago

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Joining Ranges

You are given a n-by-2 matrix. Each row represents a numeric range, e.g. x = [0 5; 10 3; 20 15; 16 19; 25 25] contains...

2 years ago

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Fill a zeros matrix

The aim is to fill an array of all zeros given a numerical value and the index of row and columns for this value. 3 Inputs: ...

2 years ago

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Put two time series onto the same time basis

Use interpolation to align two time series onto the same time vector. This is a problem that comes up in <http://www.mathwork...

2 years ago

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Return a list sorted by number of consecutive occurrences

Inspired by Problem 38 by Cody Team. Given a vector x, return a vector y of the values in x sorted by the number of CONSECUTIVE...

2 years ago

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Longest run of consecutive numbers

Given a vector a, find the number(s) that is/are repeated consecutively most often. For example, if you have a = [1 2 2 2 1 ...

2 years ago

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We love vectorized solutions. Problem 1 : remove the row average.

Given a 2-d matrix, remove the row average from each row. Your solution MUST be vectorized. The solution will be tested for ac...

2 years ago

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Piecewise linear interpolation

Given an Mx2 vector and a row of M-1 integers, output a two column vector that linearly interpolates Y times between each succes...

2 years ago

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Get the elements of diagonal and antidiagonal for any m-by-n matrix

In the problem <http://www.mathworks.com/matlabcentral/cody/problems/858-permute-diagonal-and-antidiagonal Problem 858. Permute ...

2 years ago

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intersection of matrices

Given two matrices filled with ones and zeros, determine if they share a common row, column entry. These matrices are of identi...

2 years ago

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Getting the indices from a matrice

Getting the indices from a matrice. Inspired by Problem 645. Getting the indices from a vector by the great Doug Hull. Given a...

2 years ago

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"Low : High - Low : High - Turn around " -- Create a subindices vector

Let two vectors *lo* and *hi* be given. The job is to create a index vector like so idx = [lo(1):hi(1) lo(2):hi(2) ...]...

2 years ago

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Remove the two elements next to NaN value

The aim is to *remove the two elements next to NaN values* inside a vector. For example: x = [6 10 5 8 9 NaN 23 9 7 3 21 ...

2 years ago

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middleAsColumn: Return all but first and last element as a column vector

Given input A, return all but the first and last elements, arranged as a column vector. (I.e., all dimensions after the first s...

2 years ago

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Reindex a vector

You are given two vectors of equal length. Vector N has numeric values (no Inf or NaN) while vector IDX has integers. Place th...

2 years ago

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Generate N equally spaced intervals between -L and L

Given N and L, return a list of numbers (in ascending order) that divides the interval [-L L] into N equal-length segments. F...

2 years ago

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Matrix indexing with two vectors of indices

Given a matrix M and two index vectors a and b, return a row vector x where x(i) = M(a(i),b(i)).

2 years ago

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First non-zero element in each column

For a given matrix, calculate the index of the first non-zero element in each column. Assuming a column with all elements zero ...

2 years ago

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Return unique values without sorting

If the input vector A is [42 1 1], the output value B must be the unique values [42 1] The *values of B are in the s...

2 years ago

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Specific Element Count

Given a vector _v_ and a element _e_, return the number of occurrences of _e_ in _v_. Note: NaNs are equal and there may be n...

2 years ago

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Find the largest value in the 3D matrix

Given a 3D matrix A, find the largest value. Example >> A = 1:9; >> A = reshape(A,[3 1 3]); >> islargest(A) a...

2 years ago

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Set the array elements whose value is 13 to 0

Input A either an array or a vector (which can be empty) Output B will be the same size as A . All elements of A equal to 13...

2 years ago

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Return elements unique to either input

Given two numeric inputs a and b, return a row vector that contains the numbers found in only a or only b, but not both. For ex...

2 years ago

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Replicate elements in vectors

Replicate each element of a row vector (with NaN) a constant number of times. Examples n=2, A=[1 2 3] -> [1 1 2 2 3 3] ...

2 years ago

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Getting logical indexes

This is a basic MATLAB operation. It is for instructional purposes. --- Logical indexing works like this. thresh = 4...

2 years ago

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Side of a rhombus

If a rhombus has diagonals of length x and x+1, then what is the length of its side, y? <<http://upload.wikimedia.org/wikipe...

2 years ago