Community Profile

# Nikolai

### SPbPU

291 total contributions since 2012

Research scientist
Professional Interests: Fiber optic sensors, signal processing, interferometry

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Solved

Who invented zero?
We know the importance zero in computer science, mathematics... but who invented zero? Clue: He was the first in the line ...

etwa ein Jahr 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 ...

etwa ein Jahr 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...

etwa ein Jahr 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 ...

etwa ein Jahr 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...

etwa ein Jahr ago

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Magic is simple (for beginners)
Determine for a magic square of order n, the magic sum m. For example m=15 for a magic square of order 3.

etwa ein Jahr ago

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Make a random, non-repeating vector.
This is a basic MATLAB operation. It is for instructional purposes. --- If you want to get a random permutation of integer...

etwa ein Jahr ago

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Return area of square
Side of square=input=a Area=output=b

etwa ein Jahr ago

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Maximum value in a matrix
Find the maximum value in the given matrix. For example, if A = [1 2 3; 4 7 8; 0 9 1]; then the answer is 9.

etwa ein Jahr ago

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Assigning a sum
* Write a statement that assigns numCoins with numNickels + numDimes.

fast 4 Jahre ago

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Logic variables
* Assign isAvailable with true.

fast 4 Jahre ago

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Circle area using pi
Write a statement that assigns circleArea with the circle's area given circleRadius. Use the built-in mathematical constant pi. ...

fast 4 Jahre 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 ...

fast 5 Jahre 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 ...

fast 5 Jahre ago

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Who is the smartest MATLAB programmer?
Who is the smartest MATLAB programmer? Examples: Input x = 'Is it Obama?' Output = 'Me!' Input x = 'Who ?' Ou...

fast 5 Jahre ago

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2 b | ~ 2 b
Given a string input, output true if there are 2 b's in it, false if otherwise Examples: 'Macbeth' -> false 'Publius Cor...

fast 5 Jahre 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 ...

fast 5 Jahre ago

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Find max
Find the maximum value of a given vector or matrix.

fast 5 Jahre ago

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Wind Chill Computation
On a windy day, a temperature of 15 degrees may feel colder, perhaps 7 degrees. The formula below calculates the "wind chill," i...

fast 5 Jahre 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...

fast 5 Jahre ago

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Quadratic equations have the form: ax^2 + bx + c = 0. Example: x^2 + 3x + 2 = 0, where a = 1, b = 3, and c = 2. The equation has...

fast 5 Jahre ago

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Generate a vector like 1,2,2,3,3,3,4,4,4,4
Generate a vector like 1,2,2,3,3,3,4,4,4,4 So if n = 3, then return [1 2 2 3 3 3] And if n = 5, then return [1 2 2...

fast 5 Jahre ago

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Two-output anonymous function?
Return a function handle that when applied to an input, it produces two outputs: the first is the same as the input, and the sec...

fast 5 Jahre ago

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Subset Sum
Given a vector v of integers and an integer n, return the the indices of v (as a row vector in ascending order) that sum to n. I...

fast 5 Jahre ago

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Free passes for everyone!
_Simply return the name of the coolest numerical computation software ever_ *Extra reward* (get a _freepass_): As an addit...

fast 5 Jahre 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...

fast 5 Jahre 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...

fast 5 Jahre 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...

fast 5 Jahre 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...

fast 5 Jahre ago

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Dimensions of a rectangle
The longer side of a rectangle is three times the length of the shorter side. If the length of the diagonal is x, find the width...

fast 5 Jahre ago