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Hao li


140 total contributions since 2015

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Solved


Polite numbers. Politeness.
A polite number is an integer that sums of two or more consecutive positive integers. Politeness of a positive integer is a num...

3 years ago

Solved


N-th Odious
Given index n return n-th <https://oeis.org/A000069 odious number>.

3 years ago

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Polygonal numbers
The task of <http://www.mathworks.co.uk/matlabcentral/cody/problems/5 Problem 5> is to calculate triangular numbers. By playing ...

3 years ago

Solved


Bell Number calculator
Calculate a vector of Bell numbers for sets up to length n. Bell numbers are the maximum number of partitions of a set. See the ...

3 years ago

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Armstrong Number
Determine whether the given input n-digit number is Armstrong Number or not. Return True if it is an Armstrong Number. An n-D...

3 years ago

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Is this number Munchhausen Narcissistic?
In this problem, simply return 1 if a supplied number is Munchhausen narcissistic or 0 if not. Example 153 is narcissistic...

3 years ago

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Find the 9's Complement
Find the 9's complement of the given number. An example of how this works is <http://electrical4u.com/9s-complement-and-10s-c...

3 years ago

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Smith numbers
Return true if the input is a Smith number in base ten. Otherwise, return false. Read about Smith numbers at <http://en.wikipedi...

3 years ago

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Evil Number
Check if a given natural number is evil or not. Read more at <https://oeis.org/A001969 OEIS>.

3 years ago

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Compute Fibonacci Number
Compute the _n_-th Fibonacci Number f(0) = 0, f(1) = 1, f(2) = 1, f(3) = 2, ... f(42) = 267914296

3 years ago

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Narcissistic number ?
Inspired by Problem 2056 created by Ted. In recreational number theory, a narcissistic number is a number that is the sum of ...

3 years ago

Solved


Kaprekar numbers
Test if the input is a Kaprekar number: <http://mathworld.wolfram.com/KaprekarNumber.html>. Return a logical true or false. ...

3 years ago

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Parasitic numbers
Test whether the first input x is an n-parasitic number: <http://en.wikipedia.org/wiki/Parasitic_number>. ( _n_ is the second in...

3 years ago

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Determine if a Given Number is a Triangle Number
*Description:* Determine if the elements of an input array are triangle numbers and return the result as an array with the sa...

3 years ago

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Solitaire Cipher
Implement the <http://en.wikipedia.org/wiki/Solitaire_(cipher) solitaire cipher>. Since this is from Wikipedia, I am capturin...

3 years ago

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How long is the longest prime diagonal?
Stanislaw Ulam once observed that if the counting numbers are <http://en.wikipedia.org/wiki/Ulam_spiral arranged in a spiral>, t...

3 years ago

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Find a subset that divides the vector into equal halves
Given a vector x, return the indices to elements that will sum to exactly half of the sum of all elements. Example: Inpu...

3 years ago

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Find the biggest empty box
You are given a matrix that contains only ones and zeros. Think of the ones as columns in an otherwise empty floor plan. You wan...

3 years 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 ...

3 years 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 ...

3 years 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 ...

3 years ago

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Implement simple rotation cypher
If given a letter from the set: [abc...xyz] and a shift, implement a shift cypher. Example: 'abc' with a shi...

3 years 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...

3 years ago

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Given a window, how many subsets of a vector sum positive
Given a vector: [1 0 -1 3 2 -3 1] and a window of 2, A sliding window would find: 1 + 0 = 1 0 - 1 = -1 ...

3 years ago

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Compute total cost
A soda costs 2 dollars. A taco costs 3 dollars. Write a statement that assigns totalCost with the total meal cost given the numb...

3 years ago

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DNA N-Gram Distribution
Given a string s and a number n, find the most frequently occurring n-gram in the string, where the n-grams can begin at any poi...

3 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...

3 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...

3 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...

3 years 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...

3 years ago

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