46 lines
1.2 KiB
Python
46 lines
1.2 KiB
Python
import itertools
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def solve(file):
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grid = [l.strip() for l in file]
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ny = len(grid)
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nx = len(grid[0])
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def get(p):
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x,y = p
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if 0 <= x < nx and 0 <= y < ny:
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return grid[y][x]
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return '.'
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def flood(initial_point):
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c = get(initial_point)
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stack = [initial_point]
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count = {} # set of points connected to x,y. value is the number of connected neighboring points
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while stack:
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p = stack.pop()
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if p not in count:
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count[p] = 0
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x,y = p
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for n in (x+1,y), (x-1,y), (x,y+1), (x,y-1):
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if get(n) == c:
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stack.append(n)
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count[p] += 1
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return count
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points = lambda: itertools.product(range(nx), range(ny))
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done = set() # set of points which have been counted as part of a shape
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total = 0
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for p in points():
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if p in done: continue
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shape = flood(p)
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done |= shape.keys()
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area = len(shape)
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perim = 0
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for p,n in shape.items():
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perim += 4-n
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#print(get(p), area, perim)
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total += area * perim
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print(total)
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solve(open("sample4.in"))
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solve(open("input"))
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