117 lines
2.8 KiB
Julia
117 lines
2.8 KiB
Julia
using Pkg
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Pkg.add("Match")
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using Match
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include("utils.jl")
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function parse_input(filename)
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reverse(collect(collect(non_empty_lines(filename))[1]))
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end
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mutable struct BinaryReader
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input
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rest
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BinaryReader(input) = new(input, [])
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end
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function fill_rest(reader)
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char = pop!(reader.input)
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code = codepoint(char)
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number = code < 0x3A ? code - 0x30 : code - (0x41 - 10)
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reader.rest = reverse(parse.(Int, collect(string(number, base=2, pad=4))))
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end
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function read_bits(reader, count)
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result = []
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while length(result) < count
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if length(reader.rest) == 0
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fill_rest(reader)
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end
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push!(result, pop!(reader.rest))
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end
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result
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end
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function reader_length(reader)
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length(reader.rest) + length(reader.input) * 4
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end
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function to_int(bits)
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parse(Int, reduce(*, string.(bits)), base=2)
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end
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function parse_literal(reader, version)
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result = []
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cont = 1
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while cont == 1
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cont = read_bits(reader, 1)[1]
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result = [result; read_bits(reader, 4)]
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end
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(version, 4, to_int(result))
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end
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function parse_operator(reader, version, type)
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length_type = read_bits(reader, 1)[1]
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subpackets = []
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if length_type == 0
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subpacket_bits = to_int(read_bits(reader, 15))
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start_remaining = reader_length(reader)
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while reader_length(reader) + subpacket_bits > start_remaining
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push!(subpackets, parse_packet(reader))
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end
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else
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subpacket_count = to_int(read_bits(reader, 11))
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for _ in 1:subpacket_count
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push!(subpackets, parse_packet(reader))
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end
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end
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(version, type, subpackets)
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end
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function parse_packet(reader)
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version = to_int(read_bits(reader, 3))
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type = to_int(read_bits(reader, 3))
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if type == 4
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parse_literal(reader, version)
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else
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parse_operator(reader, version, type)
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end
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end
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function sum_versions(packet)
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result = packet[1]
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if packet[2] != 4
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result += reduce(+, sum_versions.(packet[3]))
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end
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result
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end
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function solution16_1()
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input = parse_input("16.data")
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reader = BinaryReader(input)
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packet = parse_packet(reader)
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sum_versions(packet)
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end
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function value(packet)
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@match packet[2] begin
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0 => reduce(+, value.(packet[3]))
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1 => reduce(*, value.(packet[3]))
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2 => reduce(min, value.(packet[3]))
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3 => reduce(max, value.(packet[3]))
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4 => packet[3]
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5 => value(packet[3][1]) > value(packet[3][2]) ? 1 : 0
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6 => value(packet[3][1]) < value(packet[3][2]) ? 1 : 0
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7 => value(packet[3][1]) == value(packet[3][2]) ? 1 : 0
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end
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end
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function solution16_2()
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input = parse_input("16.data")
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reader = BinaryReader(input)
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packet = parse_packet(reader)
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value(packet)
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end
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solution16_2()
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