commit 9bb419b8c48ecd581ce0c3a431046cdcd325ae79
parent 314b8485bf5fd474f161cf3a034319547a190c22
Author: Eamon Caddigan <eamon.caddigan@gmail.com>
Date: Sat, 7 Jan 2023 20:03:33 -0800
Solution to day 20, part 1.
Diffstat:
| A | src/day_20.jl | | | 78 | ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ |
1 file changed, 78 insertions(+), 0 deletions(-)
diff --git a/src/day_20.jl b/src/day_20.jl
@@ -0,0 +1,78 @@
+#!/usr/bin/env julia
+# https://adventofcode.com/2022/day/20
+using AdventOfCode
+
+example = readlines(IOBuffer("""
+ 1
+ 2
+ -3
+ 3
+ -2
+ 0
+ 4"""))
+input = readlines("data/day_20.txt")
+
+mutable struct CoordFile
+ values::Vector{Int}
+ indices::Vector{Int}
+end
+
+CoordFile(x::Vector{Int}) = CoordFile(x, collect(0:length(x)-1))
+
+CoordFile(input::Vector{<:AbstractString}) = CoordFile(parse.(Int, input))
+
+"""
+Return an Array of the elements in order.
+"""
+Base.collect(coordfile::CoordFile) = coordfile.values[sortperm(coordfile.indices)]
+
+Base.length(coordfile::CoordFile) = length(coordfile.values)
+
+function Base.getindex(coordfile::CoordFile, i)
+ coordfile.values[findfirst(x->x==i, coordfile.indices)]
+end
+
+"""
+Move an element
+"""
+function moveelement!(coordfile::CoordFile, index::Int)
+ oldindex = coordfile.indices[index]
+ newindex = oldindex +
+ mod(coordfile.values[index], length(coordfile) - 1)
+ if newindex >= length(coordfile)
+ newindex -= length(coordfile) - 1
+ end
+ for i = eachindex(coordfile.indices)
+ if coordfile.indices[i] > oldindex
+ coordfile.indices[i] -= 1
+ end
+ if coordfile.indices[i] >= newindex
+ coordfile.indices[i] += 1
+ end
+ end
+ coordfile.indices[index] = newindex
+ coordfile
+end
+
+function coordinates(coordfile::CoordFile)
+ # Find the zero
+ zeroloc = coordfile.indices[findfirst(x->x==0, coordfile.values)]
+ mapreduce(x->coordfile[mod(zeroloc + x, length(coordfile))],
+ +,
+ 1000:1000:3000)
+end
+
+function part_1(input)
+ coordfile = CoordFile(input)
+ for i = 1:length(coordfile)
+ moveelement!(coordfile, i)
+ end
+ coordinates(coordfile)
+end
+@assert part_1(example) == 3
+@info part_1(input)
+
+function part_2(input)
+ nothing
+end
+@info part_2(input)
