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# Nikolaos Nikolaou

Last seen: 4 days ago Active since 2015

Physics , Wholesale auctions , Crypto Mining , Renewable Energy

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List the semiprimes
A semiprime number—or a 2-almost prime—is the product of two prime numbers. The numbers and are semiprimes, but and are not....

5 days ago

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Sequence
Let S be a sequence of numbers Let Find for some , where and .

9 days ago

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Find Min and Max Differences in a Vector
Given an array of integers, return the absolute largest and smallest (non zero) difference between any two numbers in the array....

9 days ago

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Determine if all elements are odd
Given an array, return true if all of the elements are odd. ex. x = [3 4 1] allOdd(x) ans = false ex. x = [3 5 7; 5 9...

9 days ago

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Find the number of primes leq than input
Given an integer n, determine the number of primes less than or equal to n.

9 days ago

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Sum of 2 numbers in array
Given an array and a target sum, return true if any 2 numbers in the array sum up to the given target sum. Both numbers cannot h...

9 days ago

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Momentum Calculation
A shopping cart of mass 'm1' is traveling with velocity 'u' and collides with a second shopping cart of mass 'm2.' The two shopp...

9 days ago

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Determine whether one vector is a subset of another
While bumbling through a pair of problems in the Number Theory group, I wrote code to determine whether a vector is a subset of ...

20 days ago

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Sort vector by number of prime factors of each element
Sort a given array based on how many prime factors each term has. Sort from least to greatest and output original values. Ex: ...

1 month ago

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Return longest string in 1-D array of strings
Find the longest string in an array of strings. Return an empty string if the initial array is empty. If there are multiple stri...

1 month ago

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Extract the main diagonal of a matrix
Extract the main diagonal of a matrix and return as an array. For example, the main diagonal of the following matrix would be: ...

1 month ago

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Draw a fancy '7' in a zero matrix!
Given a x-by-x matrix filled with zeros (x is odd and > 3). Use 7s to draw a number 7 into it! Like this: x = 5, y = 7 7 7 7 7...

1 month ago

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Caesar Cipher Shift
Given a word and its encrypted version using the caesar cipher, find the shift used.

1 month ago

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Mix it up!
Given an input string S, return a new string B, that is created by taking one character from the front and then the end iterativ...

1 month ago

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Monty Python and the Holy Grail: Crossing the Bridge of Death
To cross the Bridge of Death, your function must return the numerical value for the airspeed velocity of an unladen swallow

1 month ago

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Absolute Value of the Product of Complex Numbers
Find the absolute value (modulus) of the product of two complex numbers given by a + bi and c + di.

1 month ago

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True engineer
Prove that pi is indeed equal to e. Return 1 by rounding pi and e to the nearest integer then asserting rounded pi and e are eq...

1 month ago

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Determine if a number is divisible by two
Determine whether the number is divisible by two

1 month ago

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Find two numbers that add up to the target value
Given a vector A and target n, return the indices of two numbers that add up to n. If there are multiple solutions, return the f...

1 month ago

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Determine if the number is divisible by 5 or not
Given a number, return true if it is divisble by 5

1 month ago

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Draw a X
Given an input , create a square matrix of zeros with an X of ones. Ex. n = 3 drawX(3) [ 1 0 1 0 1 0 1 0 1 ] ...

1 month ago

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Caesar Cipher
Given a input word x and a shift n, encrypt the word with caesar cipher of shift n.

1 month ago

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Determine whether a number is unprimeable
The number 204 is unprimeable because no single digit can be changed to make it prime. In contrast, the number 207 is not unprim...

1 month ago

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Find the smallest prime with n inside
Consider the sequence that begins 101, 113, 127, 131, 149, 151, 163,... Not only is every term prime, the th term is the smalles...

1 month ago

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Mean ignoring NaNs
Define a function that behaves in the same way as mean(x) and mean(x,d) except that it ignores NaNs (unless all of the values be...

2 months ago

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Cat's paw - 01
lets imagine a cat, standing on an infinitely long row of tiles. since its a 'cat', string length=3; it takes 3 tiles to stand. ...

2 months ago

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A sequence of Ones
You are given number(s) with all digits - 1. Your answer will depend on the count of 1 in the given number, for example - x1...

2 months ago

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Leyland Primes
A Leyland Number is defined as a number of the form - x^y + y^x, or, x^y - y^x (x,y)>1 Given an array of numbers(>1), check...

2 months ago

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Animated GIF Creator
This Challenge is to execute the Function Template which has a fully functional Animated GIF creator of a shape related to a Zer...

2 months ago

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Binpack Contest: Retro
The <http://www.mathworks.com/matlabcentral/contest/contests/3/rules Full Binpack Rules and examples>. This Challenge is a re...

2 months ago