advent-of-code-2k20/day8/day8.py
2020-12-08 09:24:46 +01:00

50 lines
1.7 KiB
Python

#! /usr/bin/env python3
def part1(instructions):
instruction_pointer = 0
accumulator = 0
visited_instructions = set()
while instruction_pointer not in visited_instructions: # return before executing any instruction a second time
if instruction_pointer >= len(instructions): # stop the program when ip is out of bounds
break
visited_instructions.add(instruction_pointer)
instruction, argument = instructions[instruction_pointer].split(" ")
if instruction == "acc":
accumulator += int(argument)
instruction_pointer += 1
elif instruction == "jmp":
value = int(argument)
instruction_pointer += value
else:
instruction_pointer += 1
return instruction_pointer, accumulator
def part2(instructions):
for index, line in enumerate(instructions):
permutation = generate_permutation(instructions, line, index)
if permutation is None:
continue
instruction_pointer, accumulator = part1(permutation)
if instruction_pointer == len(permutation):
return accumulator
def generate_permutation(instructions, line, index):
permutation = instructions[:]
instruction, arg = line.split(" ")
if instruction == "acc": # don't replace acc operations
return
elif instruction == "nop":
permutation[index] = f"jmp {arg}"
elif instruction == "jmp":
permutation[index] = f"nop {arg}"
return permutation
if __name__ == "__main__":
instructions = [line.rstrip() for line in open("input.txt")]
print("Part 1 : (ip, acc) ", part1(instructions)[1])
print("Part 2 : (ip, acc) ", part2(instructions))