NFA确定化的Python代码
时间: 2024-11-09 09:27:14 浏览: 29
确定化有限自动机(Deterministic Finite Automaton, DFA)是将非确定型有限自动机(Non-Deterministic Finite Automaton, NFA)转换为等价的确定型自动机的过程。这个过程通常通过构造一个状态图并应用算法来实现,如Hopcroft's Minimization Algorithm。
下面是一个简单的Python代码示例,展示如何使用字典数据结构模拟NFA到DFA的转换过程:
```python
from collections import defaultdict
def nfa_to_dfa(nfa):
# 初始化DFA
dfa = {'q0': set()}
# 模拟状态转换函数
def transition(state, input_char):
transitions = nfa.get((state, input_char), None)
if not transitions:
return None
return {df_state for df_state in transitions}
# 添加起点和接受状态
dfa['q0'] |= {nfa['start']}
accepting_states = {state for state, accept in nfa.items() if accept}
while True:
new_dfa = {}
for df_state, inputs in dfa.items():
for input_char in inputs:
next_states = transition(df_state, input_char)
if not next_states:
continue
for ns in next_states:
if ns not in new_dfa:
new_dfa[ns] = set()
new_dfa[ns] |= {input_char}
# 检查是否有新的状态添加
if len(new_dfa) == len(dfa):
break
else:
dfa = new_dfa
final_dfa = {'qF': {input_char for state, chars in dfa.items() if 'qF' in state and chars}}
dfa.update(final_dfa)
return dfa
# 使用示例
nfa_example = {
('q0', 'a'): {'q1', 'q2'},
('q0', 'b'): {'q3'},
('q1', 'a'): {'q4'},
('q1', 'b'): {'q1'},
('q2', 'a'): {'q5'},
('q2', 'b'): {'q2'},
('q3', 'a'): {'q6'},
('q3', 'b'): {'q3'},
('q4', 'a'): {'q7'},
('q4', 'b'): {'q4'},
('q5', 'a'): {'q8'},
('q5', 'b'): {'q5'},
('q6', 'a'): {'q9'},
('q6', 'b'): {'q6'},
('q7', 'a'): {'qF'},
('q7', 'b'): {'q7'},
('q8', 'a'): {'qF'},
('q8', 'b'): {'q8'},
('q9', 'a'): {'qF'},
('q9', 'b'): {'q9'},
('qF', 'a'): {},
('qF', 'b'): {},
'start': 'q0'
}
determined_dfa = nfa_to_dfa(nfa_example)
```
在这个例子中,`nfa_to_dfa`函数接收一个表示NFA的字典,它模拟了状态转移规则,并最终返回一个DFA的状态机器模型。请注意这只是一个简化版本,实际应用中可能需要更复杂的处理逻辑。
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