AdventOfCode/Python/2018/13.py

110 lines
3.3 KiB
Python

from lib import *
input = read_input(2018, 13)
carts = []
tracks = input.splitlines()
positions = set()
for y, line in enumerate(tracks):
for x in range(len(line)):
c = line[x]
if c == "^":
carts.append([x, y, 0, -1, 0])
positions.add((x, y))
tracks[y] = line = line[:x] + "|" + line[x + 1 :]
elif c == "v":
carts.append([x, y, 0, 1, 0])
positions.add((x, y))
tracks[y] = line = line[:x] + "|" + line[x + 1 :]
elif c == "<":
carts.append([x, y, -1, 0, 0])
positions.add((x, y))
tracks[y] = line = line[:x] + "-" + line[x + 1 :]
elif c == ">":
carts.append([x, y, 1, 0, 0])
positions.add((x, y))
tracks[y] = line = line[:x] + "-" + line[x + 1 :]
while True:
for cart in sorted(carts, key=lambda c: (c[1], c[0])):
x, y, dx, dy, k = cart
positions.remove((x, y))
x += dx
y += dy
if (x, y) in positions:
print(f"{x},{y}")
break
positions.add((x, y))
if tracks[y][x] == "/":
dx, dy = -dy, -dx
elif tracks[y][x] == "\\":
dx, dy = dy, dx
elif tracks[y][x] == "+":
if k == 0:
dx, dy = dy, -dx
elif k == 2:
dx, dy = -dy, dx
k = (k + 1) % 3
cart[:] = x, y, dx, dy, k
else:
continue
break
carts = []
tracks = input.splitlines()
positions = {}
crashed = set()
for y, line in enumerate(tracks):
for x in range(len(line)):
c = line[x]
if c == "^":
carts.append([x * len(tracks) + y, x, y, 0, -1, 0])
positions[(x, y)] = x * len(tracks) + y
tracks[y] = line = line[:x] + "|" + line[x + 1 :]
elif c == "v":
carts.append([x * len(tracks) + y, x, y, 0, 1, 0])
positions[(x, y)] = x * len(tracks) + y
tracks[y] = line = line[:x] + "|" + line[x + 1 :]
elif c == "<":
carts.append([x * len(tracks) + y, x, y, -1, 0, 0])
positions[(x, y)] = x * len(tracks) + y
tracks[y] = line = line[:x] + "-" + line[x + 1 :]
elif c == ">":
carts.append([x * len(tracks) + y, x, y, 1, 0, 0])
positions[(x, y)] = x * len(tracks) + y
tracks[y] = line = line[:x] + "-" + line[x + 1 :]
while True:
for cart in sorted(carts, key=lambda c: (c[2], c[1])):
i, x, y, dx, dy, k = cart
if i in crashed:
continue
positions.pop((x, y))
x += dx
y += dy
if (x, y) in positions:
crashed.add(i)
crashed.add(positions.pop((x, y)))
continue
positions[(x, y)] = i
if tracks[y][x] == "/":
dx, dy = -dy, -dx
elif tracks[y][x] == "\\":
dx, dy = dy, dx
elif tracks[y][x] == "+":
if k == 0:
dx, dy = dy, -dx
elif k == 2:
dx, dy = -dy, dx
k = (k + 1) % 3
cart[:] = i, x, y, dx, dy, k
if len(carts) - len(crashed) == 1:
for i, x, y, *_ in carts:
if i not in crashed:
print(f"{x},{y}")
break
else:
continue
break