52 lines
1.2 KiB
Python
52 lines
1.2 KiB
Python
#!/usr/bin/env python3
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import re
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lines = (x.strip().replace(" ", "") for x in open("input.txt"))
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def calc(a, b, pop):
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return a+b if pop == "+" else a*b
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def pres(pop):
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if pop == "+":
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return 2
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if pop == "*":
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return 1
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return 0
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def evaluate(line):
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stack = []
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postfix = [0]
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pos = -1
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for char in "("+line+")":
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pos += 1
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if char == '(':
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stack.append("(")
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elif char == ')':
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while True:
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pop = stack.pop()
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if pop == '(':
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break
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a, b = postfix.pop(), postfix.pop()
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postfix.append(calc(a, b, pop))
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elif char in "0123456789":
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postfix[-1] = postfix[-1] * 10 + int(char)
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elif char in "*+":
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while True:
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pop = stack.pop()
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if pres(pop) <= pres(char):
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stack.append(pop)
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stack.append(char)
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postfix.append(0)
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break
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a, b = postfix.pop(), postfix.pop()
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postfix.append(calc(a, b, pop))
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else:
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raise SystemError("Invalid char: "+char)
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return postfix[0]
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print(sum(evaluate(line) for line in lines))
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