53 lines
1.8 KiB
EmacsLisp
53 lines
1.8 KiB
EmacsLisp
;; -*- lexical-binding: t; -*-
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;; Advent of Code 2019 - Day 2
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(require 'dash)
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(require 'ht)
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(defvar day2/input
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[1 0 0 3 1 1 2 3 1 3 4 3 1 5 0 3 2 1 9 19 1 19 5 23 1 13 23 27 1 27 6 31
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2 31 6 35 2 6 35 39 1 39 5 43 1 13 43 47 1 6 47 51 2 13 51 55 1 10 55
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59 1 59 5 63 1 10 63 67 1 67 5 71 1 71 10 75 1 9 75 79 2 13 79 83 1 9
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83 87 2 87 13 91 1 10 91 95 1 95 9 99 1 13 99 103 2 103 13 107 1 107 10
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111 2 10 111 115 1 115 9 119 2 119 6 123 1 5 123 127 1 5 127 131 1 10
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131 135 1 135 6 139 1 10 139 143 1 143 6 147 2 147 13 151 1 5 151 155 1
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155 5 159 1 159 2 163 1 163 9 0 99 2 14 0 0])
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;; Puzzle 1
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(defun day2/single-op (f state idx)
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(let* ((a (aref state (aref state (+ 1 idx))))
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(b (aref state (aref state (+ 2 idx))))
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(p (aref state (+ 3 idx)))
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(result (funcall f a b)))
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(aset state p (funcall f a b))))
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(defun day2/operate (state idx)
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(pcase (aref state idx)
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(99 (aref state 0))
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(1 (day2/single-op #'+ state idx)
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(day2/operate state (+ 4 idx)))
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(2 (day2/single-op #'* state idx)
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(day2/operate state (+ 4 idx)))
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(other (error "Unknown opcode: %s" other))))
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(defun day2/program-with-inputs (noun verb)
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(let* ((input (copy-tree day2/input t)))
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(aset input 1 noun)
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(aset input 2 verb)
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(day2/operate input 0)))
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(message "Solution to day2/1: %s" (day2/program-with-inputs 12 2))
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;; Puzzle 2
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(let* ((used (ht))
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(noun 0)
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(verb 0)
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(result (day2/program-with-inputs noun verb)))
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(while (/= 19690720 result)
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(setq noun (random 100))
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(setq verb (random 100))
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(unless (ht-get used (format "%d%d" noun verb))
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(ht-set used (format "%d%d" noun verb) t)
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(setq result (day2/program-with-inputs noun verb))))
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(message "Solution to day2/2: %s%s" noun verb))
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