AoC 2017: Day 8 (Parts 1 & 2)

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import re

with open('Day8input.txt', 'r') as f:
    data = [s.strip() for s in f.read().splitlines()]

register_regex = re.compile(r"([a-z]+) (dec|inc) (-?\d+) if ([a-z]+) ([><!=]+) ([-]?\d+)")

registers = {}  # Create dict of registers and values

# First pass to find register names and set val to 0
for line in data:
    mo = re.search(register_regex, line)
    rg_id = mo.groups()
    for x in (rg_id[0], rg_id[3]):
        if x not in registers:
            registers[x] = 0

max_held = 0  # PART TWO

# Second pass perform operations on registers according to puzzle instructions
for line in data:
    mo = re.search(register_regex, line)
    # print(mo.groups())
    r = mo.groups()
    # print(r[3], registers[r[3]])
    # print(r[3:])
    if eval(' '.join([str(registers[r[3]]), r[4], r[5]])):
        if r[1] == 'inc':
            registers[r[0]] += int(r[2])
        elif r[1] == 'dec':
            registers[r[0]] -= int(r[2])
    # print(r[0], registers[r[0]], "\n")
    if max_held < max(registers.values()):
        max_held = max(registers.values())

print(max(registers.values()))  # PART ONE
print(max_held)