day_1.py

# Advent of Code Day 1 solution - https://adventofcode.com/2019/day/1

# I've made all my raw inputs strings because I assume they'd normally be input from a flat file somewhere
raw_masses = "84242,87800,131272,84629,105398,91086,99863,146591,58757,51370,108422,95689,91513,113692,79189,113603,52750,123562,147710,145313,98785,86959,89755,97093,62048,98872,145829,76682,65788,119356,124600,69459,80167,56122,117390,72303,141896,140568,82565,75431,54613,124106,104628,78531,63748,139285,111926,101999,53435,57906,58120,146795,147754,79892,65395,121551,50577,122520,66441,86009,121899,71715,112666,112863,140695,54016,78041,91757,130007,89595,142289,149842,136738,70046,89586,142234,142090,147759,85957,136288,86895,131370,71565,128290,95531,110317,115170,56454,71468,113938,64193,115562,73585,81194,92754,105826,104739,137106,104467,120320"

masses = [int(mass) for mass in raw_masses.split(',')]

# Part 1

def fuel_required(mass):
    return int(mass/3) - 2

total_fuel = sum([fuel_required(mass) for mass in masses])

print(total_fuel)

# Part 2

def fuel_required_inclusive(mass):
    fuel_counter = 0
    fuel_mass = fuel_required(mass)
    while fuel_mass > 0:
        fuel_counter += fuel_mass
        # now get the extra fuel required for this fuel and repeat
        fuel_mass = fuel_required(fuel_mass)
    return fuel_counter

total_fuel_inclusive = sum([fuel_required_inclusive(mass) for mass in masses])

print(total_fuel_inclusive)