# Tag Info

### Absolute Sums of Sidi Polynomial Coefficients

Python 2, 43 bytes f=lambda n,k=1:k/n or n*f(n,k+1)+k*f(n-1,k) Try it online! A different approach Ever since I posted this challenge, I tried to come up with a ...
• 210k

### Find the polynomial

Jelly, 3 bytes ‘b@ Try it online! Returns the polynomial as a list of coefficients. Since we know the polynomial has non-negative integer coefficients, f(b) ...
• 71.5k

### Многочлены Чебышёва (Chebyshev Polynomials)

Mathematica, 15 bytes #~ChebyshevT~x& Of course, Mathematica has a builtin. If an alternative input form is allowed (10 bytes): ...
• 13.8k

### Recover polynomial $f(x)$ from $f^2(x)$

Python 2, 638 634 608 603 572 560 508 470 bytes (without brute force as well) Tthanks to @randomdude999 for the golfing down the code by like 100 bytes as well as everyone who has helped point out ...
• 271

### Fundamental Solution of the Pell Equation

Piet, 612 codels Takes n from standard input. Outputs y then x, space-separated. Codel size 1: Codel size 4, for easier viewing: Explanation Check out this NPiet trace, which shows the program ...
• 1,721

### Discrete Convolution or Polynomial Multiplication

J, 10 8 bytes [:+//.*/ Usage: ...
• 341

### Многочлены Чебышёва (Chebyshev Polynomials)

Octave, 39 bytes @(n)round(2^n/2*poly(cos((.5:n)/n*pi))) Try it online! Explanation cos((.5:n)/n*pi) builds a vector with the ...
• 105k
Accepted

### Shamir's Secret Sharing

Jelly, 15 bytes 251©xX€⁵0¦ḅÐ€%® Expects t, n, and s as command-line arguments. Try it online! How it works ...
• 210k

### Ryley's Theorem

PARI/GP, 35 bytes r->[x=r+1/3,-x+r/3/d=x^2-r,1/9/d-1] Attempt This Online! PARI/GP, 40 bytes ...
• 48.7k

### Rotate the Roots

Mathematica, 10 Bytes Pure function which takes a function of x and substitutes in ix. #/.x->I*x& Alternative with only 7 bytes but not quite sure if it ...
• 757

• 173k

### Fundamental Solution of the Pell Equation

Piet, 184 codels This is the brute-force alternative I said (in my other answer) that I didn't want to write. It takes over 2 minutes to compute the solution for n = 13. I really don't want to try it ...
• 1,721

### Computing a specific coefficient in a product of polynomials

J, 21 19 18 bytes { ::0[:+//.@(*/)/> Try it online! -1 byte thanks to FrownyFrog J has a nice geometric idiom for multiplying polynomials, which we ...
• 33.6k

Scala 3, 49 44 bytes a=>b=>(-b*b to b*b)map(p=>a-p->p)find(_*_==b) Try it onlne! Takes (a)(b) and returns an ...
• 337

### Fibonacci polynomials

J, 13 11 bytes \$1j1#]!&i.- Attempt This Online! -2 bytes thanks to @ovs Looking at the nonzero columns, some keen eyes may have noticed that the columns look ...
• 77.5k
Python, 63 50 bytes lambda m,n,k:comb(m,k)*perm(n,k) from math import* Attempt This Online! To place $k$ rooks on an $m\times n$ chessboard, we choose $k$ ...