74 lines
1.8 KiB
Python
74 lines
1.8 KiB
Python
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# -*- encoding: utf-8 -*-
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import sys
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def move(head: tuple[int, int], command: str) -> tuple[int, int]:
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h_col, h_row = head
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if command == "L":
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head = (h_col - 1, h_row)
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elif command == "R":
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head = (h_col + 1, h_row)
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elif command == "U":
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head = (h_col, h_row + 1)
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elif command == "D":
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head = (h_col, h_row - 1)
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return head
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def follow(head: tuple[int, int], tail: tuple[int, int]) -> tuple[int, int]:
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h_col, h_row = head
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t_col, t_row = tail
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# cover, nothing to do
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if head == tail:
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pass
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elif h_col == t_col and abs(h_row - t_row) > 1:
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diff = (h_row - t_row) // abs(h_row - t_row)
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tail = (t_col, t_row + diff)
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elif h_row == t_row and abs(h_col - t_col) > 1:
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diff = (h_col - t_col) // abs(h_col - t_col)
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tail = (t_col + diff, t_row)
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elif abs(h_col - t_col) > 1 or abs(h_row - t_row) > 1:
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c_diff = (h_col - t_col) // abs(h_col - t_col)
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r_diff = (h_row - t_row) // abs(h_row - t_row)
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tail = (t_col + c_diff, t_row + r_diff)
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return tail
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def run(commands: list[str], n_blocks: int) -> list[tuple[int, int]]:
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blocks = [(0, 0) for _ in range(n_blocks)]
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visited = [blocks[-1]]
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for command in commands:
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blocks[0] = move(blocks[0], command)
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for i in range(0, n_blocks - 1):
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blocks[i + 1] = follow(blocks[i], blocks[i + 1])
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visited.append(blocks[-1])
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return visited
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lines = sys.stdin.read().splitlines()
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# flatten the commands
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commands: list[str] = []
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for line in lines:
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d, c = line.split()
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commands.extend(d * int(c))
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visited_1 = run(commands, n_blocks=2)
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print(f"answer 1 is {len(set(visited_1))}")
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visited_2 = run(commands, n_blocks=10)
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print(f"answer 2 is {len(set(visited_2))}")
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