Day 12

12.py

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+#!/usr/bin/python3
+
+with open('12.txt', 'r') as file:
+    instr = list(map(str.split, map(str.strip, file.readlines())))
+
+def value(x):
+    try:
+        return int(x)
+    except ValueError:
+        return registers[x]
+
+def cpy(args): registers[args[1]] = value(args[0])
+def inc(args): registers[args[0]] += 1
+def dec(args): registers[args[0]] -= 1
+def jnz(args): global pc; pc += (0 if value(args[0]) == 0 else value(args[1]) - 1)
+
+def run():
+    global pc
+    while pc < len(instr):
+        globals()[instr[pc][0]](instr[pc][1:])
+        pc += 1
+
+registers = {'a': 0, 'b': 0, 'c': 0, 'd': 0}
+pc = 0
+run()
+
+print("Stage 1: %s" % registers['a'])
+
+registers = {'a': 0, 'b': 0, 'c': 1, 'd': 0}
+pc = 0
+run()
+
+print("Stage 2: %s" % registers['a'])

12.txt

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+cpy 1 a
+cpy 1 b
+cpy 26 d
+jnz c 2
+jnz 1 5
+cpy 7 c
+inc d
+dec c
+jnz c -2
+cpy a c
+inc a
+dec b
+jnz b -2
+cpy c b
+dec d
+jnz d -6
+cpy 13 c
+cpy 14 d
+inc a
+dec d
+jnz d -2
+dec c
+jnz c -5