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adventofcode2022
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day 19 more optimizations

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magical 2022-12-19 12:51:41 -08:00
parent 634e0e7eaa
commit 47c10a1027
1 changed files with 23 additions and 2 deletions
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day19/sol.py
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@ -56,15 +56,36 @@ def simulate(blueprint, minutes=24):
buckets[minutes].sort(reverse=True)
#print(minutes, buckets[minutes][:1])
for _, robots, resources in buckets[minutes][:limit]:
if robots[3]:
if 1:
geodes = robots[3]*minutes + resources[3]
if geodes > max_geodes:
max_geodes = geodes
elif geodes < max_geodes:
# if the number of geodes we could get if we stopped building robots
# is less than the max such number we've seen so far,
# then prune this node.
#
# this seems like it would be too greedy a rule, but
# somehow it actually works. (i think this is equivalant to
# the rule "always build a geode robot as soon as you can"
# and its validity depends on the input data. (in fact it
# *doesn't* work for the first sample blueprint for part 2.
# but it works on my input so w/e)
#
# decreases the search space enormously
continue
for robot, cost in items:
i = robot_number[robot]
if robots[i] >= rmax[i]:
# don't build more of 1 robot than we can spend in 1 minute
continue
if robot != 'geode' and robots[i]*minutes + resources[i] >= minutes*rmax[i]:
# insight from reddit: if we have enough resources on hand and enough
# mining capacity to build any robot that needs it every turn until
# time is up, then we don't need to build any more of that kind of robot
#
# this provides a minor speed-up over just doing the simpler check
continue
# figure out how soon we can afford it
wait = 0
@ -117,6 +138,6 @@ def solve2(input):
return t
assert solve(sample) == 33
#solve(input)
solve(input)
solve2(input)