72 lines
1.9 KiB
Python
72 lines
1.9 KiB
Python
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#!/usr/bin/env python
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# 2021 - Advent Of Code - 14 part 2
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from collections import Counter
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def parse_file(file):
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poly_list = []
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insertion_rules = {}
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with open(file) as f:
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poly_str = list(f.readline().strip())
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for i, p in enumerate(poly_str):
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if i + 1 == len(poly_str):
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break
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pair = '' + p + poly_str[i + 1]
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poly_list.append(pair)
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f.readline()
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for line in f.readlines():
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pair, insert = line.strip().split(' -> ')
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insertion_rules[pair] = [pair[0] + insert, insert + pair[1]]
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f_l = poly_str[0], poly_str[-1]
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return poly_list, insertion_rules, f_l
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def step_poly(init_count, ruleset):
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new_count = dict.fromkeys(ruleset.keys(), 0)
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for p in init_count.keys():
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nb = init_count[p]
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p1, p2 = ruleset[p]
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new_count[p1] += nb
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new_count[p2] += nb
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return new_count
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# poly, rules, first_last = parse_file('input_example.txt')
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poly, rules, first_last = parse_file('input.txt')
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print(f'poly: {poly}')
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print(f'rules: {rules}')
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poly_count = dict.fromkeys(rules.keys(), 0)
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for polymer in poly:
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poly_count[polymer] += 1
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print(f'init count: {poly_count}')
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for s in range(40):
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# print(f'step: {s}')
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poly_count = step_poly(poly_count, rules)
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print(f'poly count: {poly_count}')
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elements = set([k for key in poly_count.keys() for k in (key[0], key[1])])
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print(f'elements: {elements}')
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elem_count = dict.fromkeys(elements, 0)
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for polymer in poly_count.keys():
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elem_count[polymer[0]] += poly_count[polymer]
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elem_count[polymer[1]] += poly_count[polymer]
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# remove double count, and fix first and last element
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elem_count[first_last[0]] += 1
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elem_count[first_last[1]] += 1
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elem_count = {k: int(v/2) for k, v in elem_count.items()}
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print(f'fixed elem count: {elem_count}')
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c = Counter(elem_count).most_common()[0][1] - Counter(elem_count).most_common()[-1][1]
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print(c)
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