Bruno BELANYI
f9fc9fbd6b
This is mostly about unused imports. A couple errors remain, but are fine in my book (using `l` as a variable name, assigning a lambda to a variable).
80 lines
1.5 KiB
Python
Executable file
80 lines
1.5 KiB
Python
Executable file
#!/usr/bin/env python
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import sys
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from typing import List
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"""
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E : T [ * T ]*
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T : G [ + G ]*
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G : '(' E ')' | CONSTANT
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"""
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def parse_g(expr: List[str]) -> int:
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top = expr.pop(0)
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if top == "(":
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ans = parse_e(expr)
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assert expr.pop(0) == ")"
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return ans
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return int(top)
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def parse_t(expr: List[str]) -> int:
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lhs = parse_g(expr)
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while len(expr) and expr[0] == "+":
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expr.pop(0)
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rhs = parse_g(expr)
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lhs += rhs
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return lhs
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def parse_e(expr: List[str]) -> int:
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lhs = parse_t(expr)
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while len(expr) and expr[0] == "*":
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expr.pop(0)
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rhs = parse_t(expr)
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lhs *= rhs
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return lhs
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def parse_infix(input: List[str]) -> int:
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"""
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Parses the given string in infix notation.
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"""
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ans = parse_e(input)
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assert len(input) == 0
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return ans
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def tokenize(expr: str) -> List[str]:
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res = []
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def split_tok(tok: str) -> None:
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if "(" not in tok and ")" not in tok:
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res.append(tok)
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if "(" in tok:
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res.append("(")
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split_tok(tok[1:])
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if ")" in tok:
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split_tok(tok[:-1])
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res.append(")")
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for tok in expr.split():
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split_tok(tok)
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return res
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def solve(raw: List[str]) -> int:
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return sum(parse_infix(tokenize(expr)) for expr in raw)
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def main() -> None:
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input = [line.strip() for line in sys.stdin.readlines()]
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print(solve(input))
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if __name__ == "__main__":
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main()
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