aoc-2020-python-day8-part2.py

import sys

def get_input():
    with open('./input8.txt') as inp:
        return inp.read().strip().split('\n')


def finishes(ops):
    visited = set()
    acc = 0
    cursor = 0

    while True:

        if cursor in visited:
            return False, None

        if cursor > len(ops) -1:
            return True, acc

        visited.add(cursor)

        op, oper = ops[cursor].split(' ')

        if op == 'acc':
            acc += int(oper)
            cursor += 1
        elif op == 'jmp':
            cursor += int(oper)
        else:
            cursor += 1


def alter(ops, i):

    r = []

    for ix, op in enumerate(ops):

        cmd, oper = op.split(' ')

        if cmd in ['jmp', 'nop'] and ix == i:
            r.append(' '.join(['nop' if cmd == 'jmp' else 'jmp', oper]))
        else:
            r.append(op)

    return r


def run():

    ops, i = get_input(), 0

    while True:
        finished, acc = finishes(alter(ops, i))
        if finished:
            return acc
        i += 1


if __name__ == "__main__":
    print(run())