60 lines
1.2 KiB
Python
60 lines
1.2 KiB
Python
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import sys
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# parse
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I = sys.stdin.read().splitlines()
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G = [list(l) for l in I]
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W = len(G[0])
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H = len(G)
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# look for S
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S = None
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for y in range(H):
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if (x := I[y].find("S")) > -1:
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S = (x,y)
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break
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# encode moves
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D = {
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'u': {'|': ( 0,-1,'u'), 'F': ( 1, 0,'r'), '7': (-1, 0,'l')},
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'r': {'-': ( 1, 0,'r'), 'J': ( 0,-1,'u'), '7': ( 0, 1,'d')},
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'd': {'|': ( 0, 1,'d'), 'L': ( 1, 0,'r'), 'J': (-1, 0,'l')},
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'l': {'-': (-1, 0,'l'), 'L': ( 0,-1,'u'), 'F': ( 0, 1,'d')},
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}
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# part 1
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poly = [S] # vertices of the polygone
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x0, y0 = S
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P = (x0+1, y0, 'r') # start at S and go right
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for _ in range(100_000):
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x, y, d = P
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poly.append((x,y))
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z = G[y][x]
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if z == 'S':
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break
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dx,dy,nd = D[d].get(z)
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P = (x+dx,y+dy,nd)
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print(len(poly)//2)
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# part 2
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from matplotlib.path import Path
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pg = Path(poly)
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J = [['.']*W for _ in range(H)]
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R = 0
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for y in range(W):
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for x in range(H):
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if (x,y) in poly:
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J[y][x] = G[y][x]
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elif pg.contains_point((x,y)):
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R += 1
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J[y][x] = "O"
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print(R)
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# plot
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J[y0][x0] = "S"
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T = str.maketrans("|-LJ7F", "│─└┘┐┌")
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with open("grid.txt","wt") as f:
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for row in J:
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print("".join(row).translate(T), file=f)
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