AoC 2021 Day3

day3.py

from collections import Counter

# Part 1
inputs = [x.strip() for x in open('inputs.txt', 'r').readlines()]

gamma_str = ''
epsilon_str = ''
for i in range(len(inputs[0])):
    col_count = Counter([x[i] for x in inputs])
    if col_count['1'] > col_count['0']:
        gamma_str += '1'
        epsilon_str += '0'
    else:
        gamma_str += '0'
        epsilon_str += '1'
        
gamma, epsilon =   int(gamma_str, 2), int(epsilon_str, 2)      
p1 = gamma * epsilon
print(f'Part 1: {p1}')


# Part 2
ox_str = ''
co2_str = ''
ox_lst = co2_lst = inputs


for i in range(len(inputs[0])):
    ox_cnt = Counter([x[i] for x in ox_lst])
    co2_cnt = Counter([x[i] for x in co2_lst])
    if ox_lst:
        if ox_cnt['0'] > ox_cnt['1']:
            ox_lst = [x for x in ox_lst if x[i] == '0']
        else:
            ox_lst = [x for x in ox_lst if x[i] == '1']
        try:
            ox_str = ox_lst[0]
        except:
            break
    if co2_lst:
        if co2_cnt['0'] > co2_cnt['1']:    
            co2_lst = [x for x in co2_lst if x[i] == '1']
        else:
            co2_lst = [x for x in co2_lst if x[i] == '0']
        try:
            co2_str = co2_lst[0]
        except:
            break

ox, co2 = int(ox_str ,2), int(co2_str ,2)
p2 = ox * co2
print(f'Part 2: {p2}')