104 lines
2.2 KiB
Python
104 lines
2.2 KiB
Python
import operator
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lines = []
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for line in open("input"):
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lines.append(line.split())
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unused = lines
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scope = {}
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while unused:
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lines, unused = unused, []
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for words in lines:
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refs = [x for x in words[1:] if x.isalpha()]
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if any(r not in scope for r in refs):
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unused.append(words)
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continue
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dst = words[0].rstrip(':')
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if len(words) == 2:
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_, src = words
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scope[dst] = int(src)
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continue
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_, x, op, y = words
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scope[dst] = (op, scope[x], scope[y])
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optab = {
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'*': operator.mul,
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'/': operator.floordiv,
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'+': operator.add,
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'-': operator.sub,
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}
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def eval(x):
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if type(x) == int:
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return x
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op = x[0]
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args = [eval(a) for a in x[1:]]
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return optab[op](*args)
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root = scope['root']
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print(eval(root))
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def solve(x):
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_, left, right = x
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humn = scope['humn']
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path = set()
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def find(x):
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if x is humn:
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path.add(x)
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return True
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if type(x) is tuple:
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for a in x:
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if find(a):
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path.add(x)
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return True
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else:
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return False
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return False
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x, y = left, right
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if not find(x):
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find(y)
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x, y = y, x
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#print(x)
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assert x in path
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y = eval(y)
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while x is not humn:
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assert len(x) == 3
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op, a, b = x
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if op == '/':
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if a in path:
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y = ('*', y, b)
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else:
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raise ValueError("ruh-roh")
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elif op == '*':
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if a in path:
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y = ('/', y, b)
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else:
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y = ('/', y, a)
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elif op == '+':
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if a in path:
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y = ('-', y, b)
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else:
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y = ('-', y, a)
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elif op == '-':
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if a in path:
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# x - b = y => x = y + b
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y = ('+', y, b)
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else:
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# a - x = y => x = a - y
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y = ('-', a, y)
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else:
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raise ValueError("unknown op "+repr(op))
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if a in path:
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x = a
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else:
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x = b
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return eval(y)
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print(solve(root))
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