94 lines
1.9 KiB
Python
94 lines
1.9 KiB
Python
from collections import deque
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from output import answer
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n = 10
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title = "Pipe Maze"
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D = (-1, 0), (0, 1), (1, 0), (0, -1)
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C = {
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(-1, 0): ["|", "7", "F"],
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(0, 1): ["-", "7", "J"],
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(1, 0): ["|", "L", "J"],
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(0, -1): ["-", "L", "F"],
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}
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A = {
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"S": [0, 1, 2, 3],
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"-": [1, 3],
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"|": [0, 2],
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"F": [1, 2],
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"L": [0, 1],
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"7": [2, 3],
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"J": [0, 3],
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}
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@answer(1, "Farthest away pipe is at {}")
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def part_1(presolved):
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return presolved[0]
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@answer(2, "{} spots are encapsulated by pipes")
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def part_2(presolved):
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return presolved[1]
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def presolve(data):
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matrix = data.split()
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w = len(matrix[0])
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h = len(matrix)
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q = deque()
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visited = set()
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for r in range(h):
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if "S" in matrix[r]:
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start = (r, matrix[r].index("S"))
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q.append(start)
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break
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while q:
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o = q.popleft()
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visited.add(o)
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for di in A[matrix[o[0]][o[1]]]:
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d = D[di]
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r = o[0] + d[0]
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c = o[1] + d[1]
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if r >= 0 and r < h and c >= 0 and c < w:
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t = matrix[r][c]
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p = (r, c)
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if p not in visited and t != "." and t in C[d]:
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q.append(p)
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p1 = len(visited) // 2
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p2 = 0
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for y in range(h):
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for x in range(w):
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if (y, x) in visited:
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continue
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crosses = 0
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y2, x2 = y, x
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while y2 < h and x2 < w:
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c2 = matrix[y2][x2]
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if (y2, x2) in visited and c2 not in "L7":
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crosses += 1
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x2 += 1
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y2 += 1
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if crosses % 2 == 1:
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p2 += 1
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return p1, p2
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if __name__ == "__main__":
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with open("./input/10.txt", "r") as f:
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inp = f.read()
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inp = presolve(inp)
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a = part_1(inp)
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b = part_2(inp)
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assert a == 6846
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assert b == 325
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