DNF算法的代码
时间: 2023-10-12 21:11:22 浏览: 67
DNF算法是指将逻辑表达式转换为与或非(DNF)形式的算法,这里提供一份Python代码实现:
```python
def dnf(expression):
variables = set()
clauses = []
for clause in expression.split("∧"):
literals = []
for literal in clause.split("∨"):
if literal.startswith("!"):
variables.add(literal[1:])
literals.append((False, literal[1:]))
else:
variables.add(literal)
literals.append((True, literal))
clauses.append(literals)
truth_table = []
for i in range(2**len(variables)):
truth_values = {}
for j, variable in enumerate(variables):
truth_values[variable] = bool((i >> j) & 1)
truth_table.append(truth_values)
dnf_clauses = []
for truth_values in truth_table:
if all(any(literal_value == truth_values[literal_variable] for literal_value, literal_variable in clause) for clause in clauses):
dnf_clause = []
for variable, value in truth_values.items():
if not value:
dnf_clause.append((False, variable))
else:
dnf_clause.append((True, variable))
dnf_clauses.append(dnf_clause)
return "∨".join("∧".join(("!" if not value else "") + variable for value, variable in clause) for clause in dnf_clauses)
```
其中,`expression`参数是逻辑表达式,例如`"p ∧ q ∨ !p ∧ r"`。函数首先将表达式转换为子句的列表,每个子句包含多个文字。然后,函数生成真值表并计算出每个子句是否满足。最后,函数使用满足子句的变量值生成DNF子句,并将其组合成DNF表达式。
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