54 lines
1.5 KiB
Python
54 lines
1.5 KiB
Python
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from collections import defaultdict
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from math import inf
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with open("input15.txt") as f:
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lines = [line.rstrip() for line in f]
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plan = [list(map(int, line)) for line in lines]
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dim = len(plan)
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ndim = dim * 5
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# wanted to try something other than the yearly dijkstra, so overkill and
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# incomplete bellman-ford, precedents skipped for laughable gains.
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def solve(dimension, risk_f):
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dists = defaultdict(lambda: inf)
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dists[(0, 0)] = 0
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changed = True
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while changed:
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changed = False
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for x in range(dimension):
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for y in range(dimension):
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p = (x, y)
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dist = dists[p]
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near = []
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if x > 0:
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near.append((x - 1, y))
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if x < dimension - 1:
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near.append((x + 1, y))
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if y > 0:
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near.append((x, y - 1))
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if y < dimension - 1:
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near.append((x, y + 1))
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for n in near:
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nx, ny = n
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risk = risk_f(nx, ny)
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if dist + risk < dists[n]:
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changed = True
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dists[n] = dist + risk
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return dists
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def risk_f1(nx, ny):
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return plan[nx][ny]
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def risk_f2(nx, ny):
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risk = (plan[nx % dim][ny % dim] + nx // dim + ny // dim)
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while risk >= 10:
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risk -= 9
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return risk
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print(solve(dim, risk_f1)[(dim - 1, dim - 1)])
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print(solve(ndim, risk_f2)[(ndim - 1, ndim - 1)])
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