# Tagged Questions

Mathematical questions about Algorithms, including the analysis of algorithms, combinatorial algorithms, proofs of correctness, invariants, and semantic analyses. See also (computational-mathematics) and (computational-complexity).

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### What can be a good programming algorithm to solve the given equation other than the brute force? [closed]

Find all $x$, $y$ and $z$ for $n=100$; $$x^2 + y^2 + z^2 = n$$ $x,\ y,$ and $z$ should be positive integers.
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### Determining when two binary strings represent the same necklace or when one binary string is periodic

An equivalence relation on binary strings calls two strings equivalent if one can be obtained from the other by a cyclic permutation of the characters. Combinatorialists call the equivalence classes ...
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### Scrambled Sobol

I need to do a Monte Carlo simulation in high dimension (up to 1000) where using plain Sobol (with Kuo's direction vectors) as a random number generator is not good enough. Therefore I am ...
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### Chinese Postman Problem - open walk variation

Consider the following variation of the Chinese postman problem (also known as the route inspection problem). Instead of finding the shortest closed walk which traverses each edge at least once, find ...
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### number of inversions in permutation if subarray of permutation is reversed?

I have permutation(P) of numbers 1 to N (<=10^5) . Suppose I can reverse the subarray of ...
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### Fast way of suming up polynoms

You probably will think that this question is more about algorithms, but actually i'am searching for right formula. What i want to do is to compute $(A^n + A^{n-1} + .. + A + 1))$ mod $(10^9 + 7)$ ...
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### How quickly can we find a value that has large multiplicative order modulo $n$?

If we're trying to find an element modulo $n$ that has multiplicative order at least $\sqrt{n}$, how quickly can we do this? We don't know if $n$ is prime or composite, only that $n$ definitely has a ...
Given a point $p$ inside a shape $S$ described as an $n$-vertex polygon, let us say that $S$ is polar with respect to $p$ if S can be described by a polar equation $r(\theta)$ with $p$ as the origin. ...