Pregunta

In a (possibly directed) graph, is there a simple way to find all nodes reachable for a given node?
I've recently started working with MATLAB graphs. In two recent problems, I have graphs which are not known to be connected eve...

9 meses hace | 2 respuestas | 1

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Compute the Sisyphus sequence
A recent article in the New York Times featured the Online Encyclopedia of Integer Sequences, founded by Neil J.A. Sloane. One o...

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List primes of the form xy+z
Consider three consecutive integers , , and . When is the number prime? For example, if or , then the results are 17 and 37, ...

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Determine whether a number is a Gaussian prime
A Gaussian prime is a number that cannot be factored. For example, is not a Gaussian prime because it can be factored as the p...

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Express numbers as the sum of a prime, a square, and a cube
While traveling on an interstate highway, I noticed a sign that gave distances to three places. The distances were 3, 8, and 9 m...

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Determine whether a number is a Zeisel number
Do you know what is interesting about the number 1729? That’s right: it’s the third Zeisel number, a number given by , where ...

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Compute the largest number whose prime factors sum to n
This problem deals with a sequence whose tenth term is 36 because the prime factors of 36 (2, 2, 3, 3) sum to 10. The number 32 ...

alrededor de 1 año hace

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List the Moran numbers
The quotient of a Moran number and its digit sum is prime. For example, 117 and 481 are Moran numbers because 117/(1+1+7) is 13 ...

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List the cuban primes
The number 61 is a cuban prime because it is prime and the difference two cubes, 64 and 125. Write a function to list the cuba...

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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....

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Compute the bubble popper fidget spinner sequence
A fidget spinner is a toy made of multiple lobes that pivot on a ball bearing. In some, the lobes hold bubble poppers, or rubber...

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Factor a number into Fermi-Dirac primes
Cody Problem 58018 asked you to list the Fermi-Dirac primes, which are prime powers with exponents that are powers of 2. As note...

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List the Fermi-Dirac primes
The Fermi-Dirac “primes” are prime powers with exponents that are powers of 2. The first nine terms of the sequence are 2, 3, 4,...

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Identify de Polignac numbers
The numbers 125 and 329 can be written as the sum of a prime and a power of 2. For example, , and . The numbers 127 and 331, whi...

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List numbers such that every sum of consecutive positive integers ending in those numbers is composite
The sequence in question in this problem involves numbers such that all sums of consecutive positive integers ending with are ...

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List the two-bit primes
Each year at Christmas, my father-in-law and his partner send me the Puzzle Mania section from the New York Times. This year’s e...

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Solve an equation involving primes and fractions
Write a function to find pairs of primes and satisfying the equation where is an integer. The function should take a numbe...

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List odd twin composites
Twin primes, or prime numbers that differ by 2 (e.g., 17 and 19, 59 and 61, or 191 and 193), are the subject of several Cody pro...

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List the Beatriz numbers
Write a function to find integers less than or equal to an input value that solve the equation . The function gives the sum o...

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List the Euclid numbers
Euclid proved that the number of primes is infinite with the following argument. Suppose the primes form a finite set , , . Comp...

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Create Combination
Motivation: In many problems, we need to create combinations with the function nchoosek. In some cases, however, choices are lim...

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Usage of java.math : N Choose K with unlimited precision
Calculate the binomial coefficient nchoosek with full accuracy. This challenge may use the wonderful word of java.math that allo...

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Get ranking of a combination looking for speed.
I have the numbers pulled without replacement from the set [1 2 3 4 5 6 7 8 9 10 11 12 13]; They are then ordered from least to...

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Get ranking of a combination
I have the numbers pulled without replacement from the set [1 2 3 4 5 6 7 8 9 10 11 12 13]; They are then ordered from least to ...

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Put m balls into n boxes (again)
According to Cody Problem 1516, if I put 3 balls into 2 boxes then 1 1 1 1 1 2 1 2 2 ...

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Put m balls into n boxes
Can you find all the cases where, if I put 3 balls into 2 boxes the case is 1 1 1 1 1 2 1 ...

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Numbered lottery balls into cells
You are running a lottery, and have a number of different balls numbered 1 to N. Your job is to figure out how many different w...

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A (wrong) place for everything, and everything in its (wrong) place
You have an equal number of cups and balls, each labelled from one to N. You randomly place one ball in each cup. Determine th...

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Possible Outcomes of American Roulette
The payout for American roulette can be calculated by: payout = (38/n)-1 where n is the number of squares the bet covers. ...

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NCHOOSEK - Time Optimization
Input V —— Set of all choices, a vector of N, 1 < N < 100 K —— Number of selected choices, a scalar, 0 <= K <= N Output C ——...

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