In this series, I'll share my progress with the 2023 version of Advent of Code.
Check the first post for a short intro to this series.
You can also follow my progress on GitHub.
December 19th
The puzzle of day 19 is pretty fun, although I'm still working on the second part.
UPDATE: Part two is now also completed.
My pitfall for this puzzle: Not really so far, I hope graph walking will be the answer for part two, but that's still left to do.
UPDATE: Graph walking did the trick. I actually liked this puzzle a lot.
Solution here, do not click if you want to solve the puzzle first yourself
#!/usr/bin/env python3
import json
with open('input.txt') as infile:
lines = infile.readlines()
workflows = {}
parts = []
in_workflows = True
for line in lines:
if line.strip() == '':
in_workflows = False
continue
if in_workflows:
workflow = []
val = line.strip()[:-1].split('{')
workflows[val[0]] = val[1]
else:
part = {}
for c in line.strip()[1:-1].split(','):
val = c.split('=')
part[val[0]] = int(val[1])
parts.append(part)
def parse_exp(exp):
ch = exp[0]
operator = exp[1]
val = int(exp[2:])
return [ch, operator, val]
def revert(ch, operator, val):
return [ch, '>', val - 1] if operator == '<' else [ch, '<', val + 1]
def execute(workflow, part):
rules = workflow.split(',')
for rule in rules[:-1]:
split = rule.split(':')
exp = split[0]
target = split[1]
[ch, operator, val] = parse_exp(exp)
if operator == '<':
if part[ch] < val:
return target
else:
if part[ch] > val:
return target
return rules[-1]
def process(part):
workflow = workflows['in']
while True:
result = execute(workflow, part)
if result in ['A', 'R']:
return result
else:
workflow = workflows[result]
result = 0
for p in parts:
if process(p) == 'A':
result += p['x'] + p['m'] + p['a'] + p['s']
print(result)
nodes = edges = []
for k, v in workflows.items():
if not k in nodes:
nodes.append(k)
rules = v.split(',')
exps = []
for rule in rules[:-1]:
split = rule.split(':')
exp = split[0]
target = split[1]
[ch, op, val] = parse_exp(exp)
edges.append((k, target, exps + [[ch, op, val]]))
exps.append(revert(ch, op, val))
edges.append((k, rules[-1], exps))
def walk(node, end, path, paths, nodes):
if node == end:
paths.append(path)
return paths
else:
for e in edges:
if e[0] == node:
walk(e[1], end, path + e[2], paths, nodes + [node])
return paths
total = 0
for p in walk('in', 'A', [], [], []):
b = {'x': [1, 4000], 'm': [1, 4000], 'a': [1, 4000], 's': [1, 4000]}
for pb in p:
ch_bounds = b[pb[0]]
if pb[1] == '<' and ch_bounds[1] > pb[2] - 1:
ch_bounds[1] = pb[2] - 1
elif ch_bounds[0] < pb[2] + 1:
ch_bounds[0] = pb[2] + 1
total += (b['x'][1] - b['x'][0] + 1) * (b['m'][1] - b['m'][0] + 1) * \
(b['a'][1] - b['a'][0] + 1) * (b['s'][1] - b['s'][0] + 1)
print(total)
That's it! See you again tomorrow!
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