AoC23.py

code = [i.strip() for i in open("input.txt").readlines()]

pos = 0
reg = {'a': 12, 'b': 0, 'c': 0, 'd': 0}
while pos < len(code):
    ops = code[pos].split(' ')
    ops1 = reg[ops[1]] if ops[1].isalpha() else int(ops[1])
    if ops[0] == "cpy":
        if ops[2].isalpha(): reg[ops[2]] = ops1
    elif ops[0] == "inc":
        if ops[1].isalpha(): reg[ops[1]] += 1
    elif ops[0] == "dec":
        if ops[1].isalpha(): reg[ops[1]] -= 1
    elif ops[0] == "mul":
        reg[ops[3]] += reg[ops[2]] * reg[ops[1]]
        reg[ops[2]] = 0
        reg[ops[1]] = 0
    elif ops[0] == "tgl":
        if pos+ops1 in range(0, len(code)):
            tglops = code[pos+ops1].split(' ')
            if tglops[0] in {"dec", "tgl"}:
                code[pos+ops1] = "inc "+ ' '.join(tglops[1:])
            if tglops[0] == "inc":
                code[pos+ops1] = "dec "+ ' '.join(tglops[1:])
            if tglops[0] == "jnz":
                code[pos+ops1] = "cpy "+ ' '.join(tglops[1:])
            if tglops[0] == "cpy":
                code[pos+ops1] = "jnz "+ ' '.join(tglops[1:])
    if ops[0] == "jnz" and ops1 != 0:
        pos += reg[ops[2]] if ops[2].isalpha() else int(ops[2])
    else:
        pos += 1
print(reg)