increase speed by using a cache for positions

This commit is contained in:
Akumatic 2020-12-11 13:18:31 +01:00
parent 5b244fc2de
commit e60d0e1063
2 changed files with 48 additions and 42 deletions

View File

@ -7,50 +7,54 @@ def readFile() -> list:
with open(f"{__file__.rstrip('code.py')}input.txt", "r") as f:
return [list(line.strip()) for line in f.readlines()]
def get_positions(seats: list, x: int, y: int, rx: range, ry: range, adjacent: bool) -> list:
if adjacent: # check only adjacent tiles
positions = [(x+i, y+j) for i in range(-1,2) for j in range(-1,2) if (i,j) != (0,0)]
else: # check first seat available in direction
positions = []
for dx in range(-1,2):
for dy in range(-1,2):
if dx == 0 and dy == 0:
continue
i, j = x, y
while i + dx in rx and j + dy in ry:
i += dx
j += dy
if seats[i][j] in ("L", "#"):
positions.append((i, j))
break
def get_positions(seats: list, cache: dict, x: int, y: int):
idx = (x, y)
cache[idx] = {"adjacent": [], "next_seat": []}
return positions
for dx in range(-1, 2):
for dy in range(-1, 2):
if dx == 0 and dy == 0:
continue
# adjacent tiles
cache[idx]["adjacent"].append((x + dx, y + dy))
def count(seats: list, x: int, y: int, seat: str, adjacent: bool) -> int:
rx, ry = range(len(seats)), range(len(seats[0]))
positions = get_positions(seats, x, y, rx, ry, adjacent)
return sum(1 for pos in positions if pos[0] in rx and pos[1] in ry and \
seats[pos[0]][pos[1]] == seat)
# next available seat
i, j = x, y
while i + dx in cache["rx"] and j + dy in cache["ry"]:
i += dx
j += dy
if seats[i][j] in ("L", "#"):
cache[idx]["next_seat"].append((i, j))
break
def iterate(seats: list, adjacent: bool = True) -> list:
size_outer = len(seats)
size_inner = len(seats[0])
def count(seats: list, cache: dict, x: int, y: int, seat: str, selection: str) -> int:
return sum(1 for pos in cache[(x, y)][selection] if pos[0] in cache["rx"] and \
pos[1] in cache["ry"] and seats[pos[0]][pos[1]] == seat)
def create_cache(seats: list) -> dict:
cache = {"rx": range(len(seats)), "ry": range(len(seats[0]))}
for x in cache["rx"]:
for y in cache["ry"]:
get_positions(seats, cache, x, y)
return cache
def iterate(seats: list, cache: dict, adjacent: bool = True) -> list:
selection = "adjacent" if adjacent else "next_seat"
tolerance = 4 if adjacent else 5
while True:
tmp = [s[:] for s in seats]
for x in range(size_outer):
for y in range(size_inner):
for x in cache["rx"]:
for y in cache["ry"]:
if seats[x][y] == ".":
continue
elif seats[x][y] == "L":
if count(seats, x, y, "#", adjacent) == 0:
if count(seats, cache, x, y, "#", selection) == 0:
tmp[x][y] = "#"
else: # seats[x][y] == "#":
tolerance = 4 if adjacent else 5
if count(seats, x, y, "#", adjacent) >= tolerance:
if count(seats, cache, x, y, "#", selection) >= tolerance:
tmp[x][y] = "L"
if seats == tmp:
@ -58,15 +62,16 @@ def iterate(seats: list, adjacent: bool = True) -> list:
else:
seats = tmp
def part1(input: list) -> int:
seats = iterate(input)
def part1(input: list, cache) -> int:
seats = iterate(input, cache)
return sum([row.count("#") for row in seats])
def part2(input: list) -> int:
seats = iterate(input, adjacent=False)
def part2(input: list, cache) -> int:
seats = iterate(input, cache, adjacent=False)
return sum([row.count("#") for row in seats])
if __name__ == "__main__":
input = readFile()
print(f"Part 1: {part1(input)}")
print(f"Part 2: {part2(input)}")
cache = create_cache(input)
print(f"Part 1: {part1(input, cache)}")
print(f"Part 2: {part2(input, cache)}")

View File

@ -1,7 +1,7 @@
# SPDX-License-Identifier: MIT
# Copyright (c) 2020 Akumatic
from code import part1, part2, iterate
from code import part1, part2, iterate, create_cache
def test():
input = [['L', '.', 'L', 'L', '.', 'L', 'L', '.', 'L', 'L'],
@ -14,7 +14,8 @@ def test():
['L', 'L', 'L', 'L', 'L', 'L', 'L', 'L', 'L', 'L'],
['L', '.', 'L', 'L', 'L', 'L', 'L', 'L', '.', 'L'],
['L', '.', 'L', 'L', 'L', 'L', 'L', '.', 'L', 'L']]
assert iterate(input) == [
cache = create_cache(input)
assert iterate(input, cache) == [
['#', '.', '#', 'L', '.', 'L', '#', '.', '#', '#'],
['#', 'L', 'L', 'L', '#', 'L', 'L', '.', 'L', '#'],
['L', '.', '#', '.', 'L', '.', '.', '#', '.', '.'],
@ -25,7 +26,7 @@ def test():
['#', 'L', '#', 'L', '#', '#', 'L', '#', 'L', '#'],
['#', '.', 'L', 'L', 'L', 'L', 'L', 'L', '.', 'L'],
['#', '.', '#', 'L', '#', 'L', '#', '.', '#', '#']]
assert iterate(input, adjacent=False) == [
assert iterate(input, cache, adjacent=False) == [
['#', '.', 'L', '#', '.', 'L', '#', '.', 'L', '#'],
['#', 'L', 'L', 'L', 'L', 'L', 'L', '.', 'L', 'L'],
['L', '.', 'L', '.', 'L', '.', '.', '#', '.', '.'],
@ -36,8 +37,8 @@ def test():
['L', 'L', 'L', '#', '#', '#', 'L', 'L', 'L', '#'],
['#', '.', 'L', 'L', 'L', 'L', 'L', '#', '.', 'L'],
['#', '.', 'L', '#', 'L', 'L', '#', '.', 'L', '#']]
assert part1(input) == 37
assert part2(input) == 26
assert part1(input, cache) == 37
assert part2(input, cache) == 26
print("Passed tests for", input)
if __name__ == "__main__":