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#!/usr/bin/env python
import numpy as np
import re
split_pattern = re.compile('(x|y)=([\d]*)')
xMax = yMax = 0
with open('day13.txt') as data:
coords = []
for line in data:
if line == '\n':
break
else:
x, y = map(int, line.strip().split(','))
xMax = max(xMax, x)
yMax = max(yMax, y)
coords += [(x, y)]
splits = []
for line in data:
splits += [split_pattern.search(line.strip()).group(1, 2)]
thermal = np.zeros((xMax+1, yMax+1)).astype(bool)
for x, y in coords:
thermal[x, y] = True
# part 1
def fold_map(split):
# folds always fold the map in half
axis, val = split[0], int(split[1])
if axis == 'x':
folded = np.flip(thermal[val+1:], 0)
length = folded.shape[0]
thermal[val-length:val] = thermal[val-length:val] | folded
return thermal[:val]
else:
folded = np.flip(thermal[:, val+1:], 1)
length = folded.shape[1]
thermal[:, val-length:val] = thermal[:, val-length:val] | folded
return thermal[:, :val]
# part 1
print(np.count_nonzero(fold_map(splits[0])))
# part 2
for split in splits:
thermal = fold_map(split)
thermal_str = thermal.astype(str)
thermal_str[thermal] = "*"
thermal_str[~thermal] = " "
for line in thermal_str.T:
print("".join(line))
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