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adventofcode2022
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day 17 python tweaks

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magical 2022-12-17 13:17:35 -08:00
parent 8c1696fa32
commit bbc4075137
1 changed files with 24 additions and 10 deletions
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32
day17/sol.py
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@ -10,7 +10,6 @@ rocks = [
wall = 0b10000000_10000000_10000000_10000000_10000000 wall = 0b10000000_10000000_10000000_10000000_10000000
jets = ">>><<><>><<<>><>>><<<>>><<<><<<>><>><<>>" jets = ">>><<><>><<<>><>>><<<>>><<<><<<>><>><<>>"
jets = open("input").read().strip() jets = open("input").read().strip()
@ -20,10 +19,10 @@ def ceil(n):
return n return n
def drop(a, r, jets): def drop(a, r, jets):
# start falling
h = ceil(a.bit_length()) + 8*3 h = ceil(a.bit_length()) + 8*3
numjets = 0 numjets = 0
while True: while True:
# push left or right
j = next(jets) j = next(jets)
if j == '<': if j == '<':
x = (r<<1) x = (r<<1)
@ -48,14 +47,28 @@ def drop(a, r, jets):
return a, numjets return a, numjets
def head(a): def head(a):
# technically this isn't sufficient.
# you could imagine a stack of overhangs like
#
# |# #|
# |#### #|
# |# #|
# |# #|
# |# ###|
# |# #|
#
# that a rock might be able to navigate through indefinitely,
# but our stacks are much messier than that, so no need to worry.
#
# we could probably just take the top 10 or so rows and call it good.
h = ceil(a.bit_length()) h = ceil(a.bit_length())
x = 0 x = 0x80
while h >= 8 and x < 0x7f: while h >= 8:
h -= 8 h -= 8
x |= (a>>h)&0xff x |= (a>>h)&0xff
if x >= 0x7f: if x == 0xff:
return a>>h return a>>h
return 0 return a
def height(a): def height(a):
return ceil(a.bit_length())//8 return ceil(a.bit_length())//8
@ -93,14 +106,15 @@ try:
#for i in reversed(range(0,a.bit_length(),8)): #for i in reversed(range(0,a.bit_length(),8)):
# print("{:08b}".format((a>>i)&0xff)) # print("{:08b}".format((a>>i)&0xff))
#print() #print()
finally: except:
pass #print(i, j, stopped) print(i, j, stopped)
raise
b, old = seen[(i,j,head(a))] b, old = seen[(i,j,head(a))]
sdiff = stopped - old sdiff = stopped - old
hdiff = height(a) - height(b) hdiff = height(a) - height(b)
goal = 1000000000000 goal = 10**12
rounds, extra = divmod(goal - stopped, sdiff) rounds, extra = divmod(goal - stopped, sdiff)
for _ in range(extra): for _ in range(extra):
r = next(rocki) r = next(rocki)