132 lines
3.3 KiB
Python
132 lines
3.3 KiB
Python
import sys
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from collections import defaultdict
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map = [x.strip() for x in sys.stdin]
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print(map)
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Y = len(map)
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X = len(map[0])
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assert all(len(row) == X for row in map)
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N,E,S,W = 1,2,4,8
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unknown = 0b11111
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grid = {}
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start = None
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for i, row in enumerate(map):
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for j,c in enumerate(row):
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d = 0
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if c == ".": d = 0
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elif c == "7": d = W|S
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elif c == "J": d = N|W
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elif c == "L": d = N|E
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elif c == "F": d = S|E
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elif c == "|": d = N|S
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elif c == "-": d = W|E
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elif c == "S":
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d = unknown
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start = (i,j)
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else:
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raise Exception("invalid char %s at (%s,%s)" % (c, i, j))
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grid[i,j] = d
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#print(grid)
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def find_loop(grid, start):
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front = [(0,start)]
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dist = {}
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count = defaultdict(int)
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count[start] -= 1
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def push(i,j,from_):
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if grid.get((i,j),0)&from_:
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front.append((cost+1, (i,j)))
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while front:
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front.sort()
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cost, n = front.pop(0)
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if n not in grid:
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continue
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count[n] += 1
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if n in dist:
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continue
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dist[n] = cost
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i, j = n
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d = grid[n]
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if d&N: push(i-1,j,S)
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if d&S: push(i+1,j,N)
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if d&W: push(i,j-1,E)
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if d&E: push(i,j+1,W)
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#print(count.values())
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if not all(c == 2 for c in count.values()):
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# not a loop
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return {}
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return dist
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def enclosedby(grid, points):
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# upsample by 3x3
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import numpy
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fill = numpy.zeros((Y*3,X*3+1), dtype='uint8')
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#fill = [[0]*(X*3) for _ in range(Y*3)]
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for i,j in points:
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d = grid[i,j]
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if d == N|S: t=[[0,1,0],[0,1,0],[0,1,0]]
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elif d == N|W: t=[[0,1,0],[1,1,0],[0,0,0]]
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elif d == N|E: t=[[0,1,0],[0,1,1],[0,0,0]]
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elif d == S|W: t=[[0,0,0],[1,1,0],[0,1,0]]
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elif d == S|E: t=[[0,0,0],[0,1,1],[0,1,0]]
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elif d == E|W: t=[[0,0,0],[1,1,1],[0,0,0]]
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else: raise Exception("invalid d=%d at (%s,%s)" % (d, i, j))
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for k in range(3):
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for l in range(3):
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fill[i*3+k, j*3+l] = t[k][l]
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def draw(fill):
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for row in fill:
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print("".join(".+O"[f] for f in row))
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draw(fill)
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# fill edges
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for i in range(Y*3):
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if fill[i, 0 ] == 0: fill[i, 0 ] = 2
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if fill[i, X*3-1] == 0: fill[i, X*3-1] = 2
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for j in range(X*3):
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if fill[ 0 , j] == 0: fill[ 0 , j] = 2
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if fill[Y*3-1, j] == 0: fill[Y*3-1, j] = 2
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# flood fill
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changed = True
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while changed:
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#draw(fill)
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changed = False
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for i in range(Y*3):
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f = (fill[i] == 2)
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f = numpy.roll(f, 1) | numpy.roll(f, -1)
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if i > 0: f |= (fill[i-1] == 2)
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if i < Y*3-1: f |= (fill[i+1] == 2)
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f[-1] = False
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f &= (fill[i] == 0)
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if f.any():
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fill[i, f] = 2
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changed = True
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draw(fill)
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# downsample
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inside = []
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for i,j in grid:
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f = [fill[i*3+k, j*3+l]==0 for k in range(3) for l in range(3)]
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if all(f):
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inside.append((i,j))
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print("inside =", inside)
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return len(inside)
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for D in [W|S, N|W, N|E, S|E, N|S, W|E]:
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grid[start] = D
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loop = find_loop(grid, start)
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if loop:
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print(D, loop.keys())
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print(max(loop.values()))
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print(enclosedby(grid, loop))
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