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113 lines
3.3 KiB
Python
113 lines
3.3 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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class Node:
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leaf_value = None
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def __init__(self, expression):
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# print('Processing', expression)
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while expression[0] == '(':
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level = 0
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split = None
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closing_bracket = None
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for idx, char in enumerate(expression):
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if char == '(':
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level += 1
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elif char == ')':
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level -= 1
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if level == 0 and closing_bracket is None:
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closing_bracket = idx
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if level == 0 and char == '*' and split is None:
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split = idx
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# print(f'Found split at {i} within {expression}')
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if closing_bracket + 1 == len(expression):
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# print('stipping unneeded parens')
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expression = expression[1:-1]
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else:
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if split is not None:
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# self.split_at(expression, split)
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self.split_at(expression, split)
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else:
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self.split_at(expression, closing_bracket + 2)
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return
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if '(' in expression:
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level = 0
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split = None
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for idx, char in enumerate(expression):
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if char == '(':
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level += 1
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elif char == ')':
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level -= 1
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if level == 0 and char == '*' and split is None:
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split = idx
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if split is not None:
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self.split_at(expression, split)
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else:
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self.split_at(expression, expression.find('+'))
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elif '*' in expression:
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self.split_at(expression, expression.find('*'))
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elif '+' in expression:
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self.split_at(expression, expression.find('+'))
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else:
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self.leaf_value = int(expression.strip())
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def split_at(self, expression, idx):
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left = expression[:idx].strip()
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right = expression[idx + 1:].strip()
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op = expression[idx]
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# print(f'Splitting "{left}" "{op}" "{right}"')
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self.left = Node(left)
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self.right = Node(right)
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self.op = op
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@ property
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def value(self):
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if self.leaf_value is not None:
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return self.leaf_value
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return calc(self.op, self.left.value, self.right.value)
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def solve(line):
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return Node(line.strip()).value
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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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# should be 16530240
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example7 = '3 + (8 * 2 * 4) * 8 * (2 + (8 * 5 + 3 * 4 + 4)) * (2 * (5 * 6))'
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print(example7, '=', solve(example7), 'should be', '16530240')
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print('Solution')
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# for expr in expressions:
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# print(expr.strip(), '=', solve(expr))
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print(sum(map(solve, expressions)))
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