This commit is contained in:
cupcakearmy 2022-11-28 23:51:45 +01:00
parent 607651d3ba
commit e3fe7fb6bc
2 changed files with 99 additions and 0 deletions

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2021/14/README.md Normal file
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# 14
This was nice! Similar to the Lanterfish one. The naive way is to have a big string, but that becomes unfeasible quickly.
The solution was to keep track of the number of combinations available and at the end divide by 2 the counted elements. Rounding up so that the first and last element is not neglected as they are not doubled.
<details>
<summary>Solutions</summary>
<ol>
<li>2988</li>
<li>3572761917024</li>
</ol>
</details>

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2021/14/python/main.py Normal file
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#!/usr/bin/env python
import math
from collections import defaultdict
from os.path import dirname, join
# Day 14
# Common
def read_input(filename):
data = join(dirname(__file__), '..', filename)
with open(data) as f:
return f.read().strip()
test = read_input('test.txt')
data = read_input('input.txt')
class Polymer:
def __init__(self, state: str, insertions: dict[str, str]):
self.state = state
self.insertions = insertions
self.states: defaultdict[str, int] = defaultdict(lambda: 0)
for i in range(len(self) - 1):
pair = self.state[i:i+2]
self.states[pair] += 1
def __len__(self):
return len(self.state)
def step(self):
new = defaultdict(lambda: 0)
for state, count in self.states.items():
if count == 0:
continue
insertion = self.insertions[state]
for key in [state[0] + insertion, insertion + state[1]]:
new[key] += count
self.states = new
def score(self):
elements = defaultdict(lambda: 0)
for state, count in self.states.items():
for element in state:
elements[element] += count
for element, count in elements.items():
elements[element] = math.ceil(elements[element]/2)
return max(elements.values()) - min(elements.values())
def flag(self, steps: int):
for _ in range(steps):
self.step()
print(self.score())
@staticmethod
def parse(data: str):
state, raw = data.split('\n\n')
lines = [
l.split(' -> ')
for l in raw.split('\n')
]
insertions = {
i[0]: i[1]
for i in lines
}
return Polymer(state.strip(), insertions)
# 1
print('1.')
polymer = Polymer.parse(test)
polymer.flag(10)
polymer = Polymer.parse(data)
polymer.flag(10)
# 2
print('\n2.')
polymer = Polymer.parse(test)
polymer.flag(40)
polymer = Polymer.parse(data)
polymer.flag(40)