Revision 3c7acc56ca8e3e28de5772a228f6930083bad1e9 authored by Jameson Nash on 24 April 2017, 18:00:03 UTC, committed by Jameson Nash on 24 April 2017, 18:00:50 UTC
1 parent e14cf14
ModInts.jl
# This file is a part of Julia. License is MIT: https://julialang.org/license
module ModInts
export ModInt
import Base: +, -, *, /, inv
struct ModInt{n} <: Integer
k::Int
ModInt{n}(k) where n = new(mod(k,n))
end
Base.show{n}(io::IO, k::ModInt{n}) =
print(io, get(io, :compact, false) ? k.k : "$(k.k) mod $n")
+{n}(a::ModInt{n}, b::ModInt{n}) = ModInt{n}(a.k+b.k)
-{n}(a::ModInt{n}, b::ModInt{n}) = ModInt{n}(a.k-b.k)
*{n}(a::ModInt{n}, b::ModInt{n}) = ModInt{n}(a.k*b.k)
-{n}(a::ModInt{n}) = ModInt{n}(-a.k)
inv{n}(a::ModInt{n}) = ModInt{n}(invmod(a.k, n))
/{n}(a::ModInt{n}, b::ModInt{n}) = a*inv(b) # broaden for non-coprime?
Base.promote_rule{n}(::Type{ModInt{n}}, ::Type{Int}) = ModInt{n}
Base.convert{n}(::Type{ModInt{n}}, i::Int) = ModInt{n}(i)
end # module
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