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lines = []
with open("2-input", "r") as fp:
lines = fp.readlines()
levels = [list(map(int, line.strip().split(" "))) for line in lines]
def is_good_level_1(level):
# 1) Is decreasing
# 2) Sliding window of two cells (x, y) => 1 <= |x-y| <= 3
# figure out if decreasing from first two
decreasing = level[0] > level[1]
for i in range(len(level) - 1):
x = level[i]
y = level[i + 1]
diff = abs(x - y)
if (decreasing and x < y) or (not decreasing and x > y) or not (diff <= 3 and diff >= 1):
return False
return True
good_levels = [level for level in levels if is_good_level_1(level)]
print(f"Round 1: {len(good_levels)}")
def check_two_levels(x, y, decreasing):
diff = abs(x - y)
return not ((decreasing and x < y)\
or (not decreasing and x > y) \
or not (diff <= 3 and diff >= 1))
def is_good_level_2(level):
# 1) Is decreasing
# 2) Sliding window of two cells (x, y) => 1 <= |x-y| <= 3
# 3) Can remove any one item to make it safe
if is_good_level_1(level):
return True
# Consider slices of the level and check if they're good
slices = [level[:i] + level[i + 1:] for i in range(len(level))]
for s in slices:
if is_good_level_1(s):
return True
return False
good_levels = [level for level in levels if is_good_level_2(level)]
print(f"Round 2: {len(good_levels)}")
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