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62 lines
1.5 KiB
Python
62 lines
1.5 KiB
Python
4 years ago
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import re
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example1 = '1 + 2 * 3 + 4 * 5 + 6'
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example2 = '1 + (2 * 3) + (4 * (5 + 6))'
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example3 = '2 * 3 + (4 * 5)'
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example4 = '5 + (8 * 3 + 9 + 3 * 4 * 3)'
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example5 = '5 * 9 * (7 * 3 * 3 + 9 * 3 + (8 + 6 * 4))'
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example6 = '((2 + 4 * 9) * (6 + 9 * 8 + 6) + 6) + 2 + 4 * 2'
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with open('input') as f:
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expressions = f.readlines()
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def calc(op, a, b):
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if op == '+':
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return a + b
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elif op == '*':
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return a * b
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else:
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raise Exception(f'Operator "{op}" not known')
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def solve(line):
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num_stack = [0]
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op_stack = ['+']
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for char in line:
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if char in [' ', '\n']:
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continue
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if char == '(':
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num_stack.append(0)
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op_stack.append('+')
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elif char == ')':
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op = op_stack.pop()
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a = num_stack.pop()
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b = num_stack.pop()
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num_stack.append(calc(op, a, b))
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elif char in ['+', '*']:
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op_stack.append(char)
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elif re.match('[0-9]', char):
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num = int(char)
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num_stack.append(int(char))
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op = op_stack.pop()
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a = num_stack.pop()
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b = num_stack.pop()
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num_stack.append(calc(op, a, b))
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# print(num_stack, op_stack)
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return num_stack.pop()
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print(example1, '=', solve(example1))
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print(example2, '=', solve(example2))
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print(example3, '=', solve(example3))
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print(example4, '=', solve(example4))
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print(example5, '=', solve(example5))
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print(example6, '=', solve(example6))
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print('Solution')
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print(sum(map(solve, expressions)))
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