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day8.py
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day8.py
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"""
Day 8: Treetop Tree House
"""
def _scan_visibility(line):
max_height = None
for height in line:
if max_height is None or height > max_height:
max_height = height
yield True
else:
yield False
def part1(lines):
"""
>>> part1(["30373", "25512", "65332", "33549", "35390"])
21
"""
lines = [line.rstrip() for line in lines]
visibilities = [list(_scan_visibility(line)) for line in lines]
for line, row in zip(lines, visibilities):
for col_index, value in enumerate(_scan_visibility(line[::-1])):
row[-1 - col_index] |= value
for col_index, line in enumerate(zip(*lines)):
line = "".join(line)
for row_index, value in enumerate(_scan_visibility(line)):
visibilities[row_index][col_index] |= value
for row_index, value in enumerate(_scan_visibility(line[::-1])):
visibilities[-1 - row_index][col_index] |= value
return sum(sum(row) for row in visibilities)
def _scan_score(line):
horizon = 0
for index, height in enumerate(line):
for horizon in range(index - 1, -1, -1):
if line[horizon] >= height:
break
yield index - horizon
def part2(lines):
"""
>>> part2(["30373", "25512", "65332", "33549", "35390"])
8
"""
lines = [line.rstrip() for line in lines]
scores = [list(_scan_score(line)) for line in lines]
for line, row in zip(lines, scores):
for col_index, value in enumerate(_scan_score(line[::-1])):
row[-1 - col_index] *= value
for col_index, line in enumerate(zip(*lines)):
line = "".join(line)
for row_index, value in enumerate(_scan_score(line)):
scores[row_index][col_index] *= value
for row_index, value in enumerate(_scan_score(line[::-1])):
scores[-1 - row_index][col_index] *= value
return max(max(row) for row in scores)
parts = (part1, part2)