Day 18 part 2
This commit is contained in:
parent
c40027f12e
commit
0a694d06f9
111
2019/day18.py
111
2019/day18.py
|
|
@ -2,63 +2,107 @@ import string
|
|||
import sys
|
||||
|
||||
from grid import Grid
|
||||
from vector import v2a
|
||||
|
||||
|
||||
EX1 = [
|
||||
"#########",
|
||||
"#b.A.@.a#",
|
||||
"#########",
|
||||
EX3 = [
|
||||
"#######",
|
||||
"#a.#Cd#",
|
||||
"##@#@##",
|
||||
"#######",
|
||||
"##@#@##",
|
||||
"#cB#Ab#",
|
||||
"#######",
|
||||
]
|
||||
EX2 = [
|
||||
"########################",
|
||||
"#f.D.E.e.C.b.A.@.a.B.c.#",
|
||||
"######################.#",
|
||||
"#d.....................#",
|
||||
"########################",
|
||||
EX4 = [
|
||||
"###############",
|
||||
"#d.ABC.#.....a#",
|
||||
"######@#@######",
|
||||
"###############",
|
||||
"######@#@######",
|
||||
"#b.....#.....c#",
|
||||
"###############",
|
||||
]
|
||||
|
||||
|
||||
def main():
|
||||
with open("day18.txt", "rt") as input_file:
|
||||
lines = input_file.readlines()
|
||||
|
||||
print(f"Part 1 answer: {find_all_keys_with_min_steps(lines)} steps.")
|
||||
|
||||
with open("day18-p2.txt", "rt") as input_file: # yeah
|
||||
lines = input_file.readlines()
|
||||
print(f"Part 2 answer: {find_all_keys_with_min_steps(lines)} steps.")
|
||||
|
||||
def find_all_keys_with_min_steps(lines):
|
||||
"""Find all keys with 1 or 4 starting points."""
|
||||
lab = Lab(lines=lines)
|
||||
lab.dumb_print()
|
||||
lab.find_positions()
|
||||
states = [(lab.start, frozenset(), 0)]
|
||||
num_robots = len(lab.starts)
|
||||
states = [(
|
||||
lab.starts[0] if num_robots == 1 else encode_posis_packed(lab.starts),
|
||||
frozenset(),
|
||||
0
|
||||
)]
|
||||
state_cache = Grid(value_factory=dict)
|
||||
num_keys = len(lab.key_pos)
|
||||
min_steps = 2**32
|
||||
num_processed = 0
|
||||
while states:
|
||||
num_processed += 1
|
||||
pos, obtained, total_steps = states.pop(0)
|
||||
one_or_more_pos, obtained, total_steps = states.pop(0)
|
||||
if len(obtained) == num_keys:
|
||||
print(f"All keys obtained in {total_steps}.")
|
||||
print(f"[Found total of {total_steps}]", end="")
|
||||
min_steps = min(min_steps, total_steps)
|
||||
continue
|
||||
|
||||
for key_name, bt in lab.get_missing_backtracks(pos, keys=obtained).items():
|
||||
steps, required, found = bt
|
||||
if len(required - obtained) > 0:
|
||||
continue
|
||||
|
||||
next_pos = lab.key_pos[key_name]
|
||||
next_obtained = obtained | found | {key_name}
|
||||
next_steps = total_steps + steps
|
||||
robot_positions = [one_or_more_pos] if num_robots == 1 else decode_posis(one_or_more_pos)
|
||||
for pos_index, pos in enumerate(robot_positions):
|
||||
for key_name, bt in lab.get_missing_backtracks(pos, keys=obtained).items():
|
||||
steps, required, found = bt
|
||||
if len(required - obtained) > 0:
|
||||
continue
|
||||
|
||||
next_pos = lab.key_pos[key_name]
|
||||
next_obtained = obtained | found | {key_name}
|
||||
next_steps = total_steps + steps
|
||||
|
||||
old_bests = state_cache.getv(next_pos[0], next_pos[1])
|
||||
if next_obtained not in old_bests or old_bests[next_obtained] > next_steps:
|
||||
print("o", end="")
|
||||
states.append((next_pos, next_obtained, next_steps))
|
||||
old_bests[next_obtained] = next_steps
|
||||
print(".", end="")
|
||||
old_bests = state_cache.getv(next_pos[0], next_pos[1])
|
||||
if next_obtained not in old_bests or old_bests[next_obtained] > next_steps:
|
||||
print("o", end="")
|
||||
if num_robots > 1:
|
||||
mpos = robot_positions.copy()
|
||||
mpos[pos_index] = next_pos
|
||||
next_pos = encode_posis_packed(tuple(mpos))
|
||||
states.append((next_pos, next_obtained, next_steps))
|
||||
old_bests[next_obtained] = next_steps
|
||||
print(".", end="")
|
||||
|
||||
if num_processed % 100 == 0:
|
||||
print(f"[{num_processed}/{len(states)}]", end="")
|
||||
sys.stdout.flush()
|
||||
print(f"Minimal number of steps to get all keys: {min_steps}.")
|
||||
|
||||
print()
|
||||
return min_steps
|
||||
|
||||
def encode_posis_packed(pt):
|
||||
p1, p2, p3, p4 = pt
|
||||
return encode_posis(p1, p2, p3, p4)
|
||||
|
||||
def encode_posis(p1, p2, p3, p4):
|
||||
return (
|
||||
(p1[0] << 24) + (p2[0] << 16) + (p3[0] << 8) + (p4[0]),
|
||||
(p1[1] << 24) + (p2[1] << 16) + (p3[1] << 8) + (p4[1]),
|
||||
)
|
||||
|
||||
def decode_posis(p):
|
||||
return [
|
||||
((p[0] & 0xFF000000) >> 24, (p[1] & 0xFF000000) >> 24),
|
||||
((p[0] & 0x00FF0000) >> 16, (p[1] & 0x00FF0000) >> 16),
|
||||
((p[0] & 0x0000FF00) >> 8, (p[1] & 0x0000FF00) >> 8),
|
||||
((p[0] & 0x000000FF) , (p[1] & 0x000000FF)),
|
||||
]
|
||||
|
||||
|
||||
class Lab(Grid):
|
||||
|
||||
|
|
@ -68,19 +112,20 @@ class Lab(Grid):
|
|||
|
||||
def __init__(self, *args, **kwargs):
|
||||
super().__init__(*args, **kwargs, value_factory=lambda: " ")
|
||||
self.start = None
|
||||
self.starts = []
|
||||
self.key_pos = {}
|
||||
self.door_pos = {}
|
||||
|
||||
def find_positions(self):
|
||||
for x, y, v in self.values_gen():
|
||||
if v == Lab.TILE_START:
|
||||
self.start = (x, y)
|
||||
self.starts.append((x, y))
|
||||
if v in string.ascii_lowercase:
|
||||
self.key_pos[v] = (x, y)
|
||||
if v in string.ascii_uppercase:
|
||||
self.door_pos[v] = (x, y)
|
||||
self.setv(self.start[0], self.start[1], Lab.TILE_PATH)
|
||||
for p in self.starts:
|
||||
self.setv(p[0], p[1], Lab.TILE_PATH)
|
||||
|
||||
def get_missing_backtracks(self, start, keys=set()):
|
||||
backtracks = {}
|
||||
|
|
|
|||
Loading…
Reference in a new issue