74 lines
2.4 KiB
Nim
74 lines
2.4 KiB
Nim
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import ./common, std/[strutils, sugar, sequtils, options, tables, sets, strformat, algorithm, pegs]
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type
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Register = int
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ALUInstruction = (string, Register, string)
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ALUState = array[4, int]
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proc parseInstruction(s: string): ALUInstruction =
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# echo s
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let ss = s.split(' ')
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let i = if ss.len > 2: ss[2] else: ""
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(ss[0], ss[1][0].ord - ord('w'), i)
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proc runALUInstructions(instructions: seq[ALUInstruction], input: string): ALUState =
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var inputs = input.reversed
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let registers = toHashSet(['w', 'x', 'y', 'z'])
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var n = 0
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for i in instructions:
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let (op, reg, arg) = i
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var narg = arg
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var num = 0
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if arg != "":
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if registers.contains(arg[0]):
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let index = arg[0].ord - 'w'.ord
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num = result[index]
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narg = &"r{index+1}"
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else: num = arg.parseInt
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if n mod 18 in [4, 5, 15, 0]:
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echo &"{result} -> {op} {narg} to r{reg+1} (Input Left: {inputs.join})"
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case op:
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of "inp": result[reg] = inputs.pop.ord - '0'.ord
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of "add": result[reg] += num
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of "mul": result[reg] *= num
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of "div": result[reg] = result[reg] div num
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of "mod": result[reg] = result[reg] mod num
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of "eql": result[reg] = (result[reg] == num).int
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inc n
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proc p1(input: Lines): uint64 =
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# repeating these 18 instructions:
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# w is used to store the input digit
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# x is zeroed
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# z is added to x
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# x is modulo'd over 26
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# z is divided by either 1 or 26 (mostly in the latter half of the inputs)
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# x is added with SOME NUMBER (sometimes negative)
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# x is ALWAYS eql'd with w and 0
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# this is meant to ensure that x is NOT equal to the input?
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# y is ALWAYS set to 25
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# y is multiplied by x, which will be 25 if x was 1 or 0 otherwise
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# so y will be 25 if x was equal to the input and 0 if not
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# y is incremented
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# 26 now, if x was equal, 1 if not
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# z is multiplied by y
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# so z
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# y is zeroed out, set to w (the input), added with SOME NUMBER, then multiplied with x
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# add y to z
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# if I need to get z to zero, I need to know where those 26-divisions are and leverage them
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# if I can ever get y to be negative, that could help a lot as well
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# probably a relatively simple way to bruteforce over this?
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let instructions = input.map(parseInstruction)
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# let oalu = instructions.runALUInstructions("13579246899999")
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# echo oalu
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let alu = instructions.runALUInstructions("99879249111111")
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echo alu
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0
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proc p2(input: Lines): uint64 =
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0
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time(&"Day 24 Part 1"): echo 24.loadInput.p1
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