59 lines
1.5 KiB
Python
Executable file
59 lines
1.5 KiB
Python
Executable file
#!/usr/bin/env python
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import sys
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from typing import NamedTuple
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class Group(NamedTuple):
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children: list["Group"]
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def solve(input: str) -> int:
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def parse_group(input: str) -> tuple[Group, str, int]:
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garbage = False
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cancel = False
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stack: list[Group] = []
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total_garbage = 0
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for i, c in enumerate(input):
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if cancel:
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assert garbage # Sanity check
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cancel = False
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continue
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if garbage:
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if c == "!":
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cancel = True
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elif c == ">":
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garbage = False
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else:
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total_garbage += 1
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continue
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if c == "<":
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garbage = True
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continue
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if c == "{":
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stack.append(Group([]))
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continue
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if c == "}":
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top = stack.pop()
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if stack:
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stack[-1].children.append(top)
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continue
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return top, input[i + 1 :], total_garbage
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assert False # Sanity check
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def parse(input: str) -> tuple[Group, int]:
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groups, input, total_garbage = parse_group(input)
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assert not input # Sanity check
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return groups, total_garbage
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_, total_garbage = parse(input.strip())
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return total_garbage
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def main() -> None:
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input = sys.stdin.read()
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print(solve(input))
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if __name__ == "__main__":
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main()
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