79 lines
1.9 KiB
Python
79 lines
1.9 KiB
Python
from lib import *
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EXAMPLE = """
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2413432311323
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3215453535623
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3255245654254
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3446585845452
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4546657867536
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1438598798454
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4457876987766
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3637877979653
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4654967986887
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4564679986453
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1224686865563
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2546548887735
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4322674655533
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"""
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def solve(i: Input, second=False):
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g = i.grid2()
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starts = [((0, 0), (0, None))]
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def is_goal(node):
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pos, _ = node
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return pos == (g.n_cols - 1, g.n_rows - 1)
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def neighbors(node):
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pos, dirs = node
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repeats, prev_dir = dirs
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nbs = []
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for dir in [NORTH, WEST, SOUTH, EAST]:
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if second:
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if repeats < 4 and prev_dir is not None and prev_dir != dir:
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continue
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if repeats == 10 and prev_dir == dir:
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continue
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else:
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if repeats == 3 and prev_dir == dir:
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continue
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if prev_dir == NORTH and dir == SOUTH:
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continue
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elif prev_dir == SOUTH and dir == NORTH:
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continue
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elif prev_dir == EAST and dir == WEST:
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continue
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elif prev_dir == WEST and dir == EAST:
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continue
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nb = add2(pos, dir)
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if not g.contains(nb):
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continue
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nbs.append((nb, (repeats + 1 if dir == prev_dir else 1, dir)))
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return nbs
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def h(node):
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pos, _ = node
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return abs(g.n_rows - 1 - pos[0]) + abs(g.n_cols - 1 - pos[1])
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def d(_, b):
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pos, _ = b
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if pos == (0, 0):
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return 0
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return int(g[pos])
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a = A_Star(starts, is_goal, h, d, neighbors)
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return a.cost
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def main():
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DAY_INPUT = "i17.txt"
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print("Example 1:", solve(Input(EXAMPLE)))
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print("Solution 1:", solve(Input(DAY_INPUT)))
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print("Example 2:", solve(Input(EXAMPLE), True))
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print("Solution 2:", solve(Input(DAY_INPUT), True))
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return
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if __name__ == "__main__":
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main()
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