构造正则表达式的简化 DFA 算法

Algorithm for Constructing the Simplified DFA of Regular Expressions

介绍了构造等价于给定正则表达式的简化确定有限自动机（ＤＦＡ）的算法．方法是首先构造与正则表达式等价的非确定有限自动机（ＮＦＡ），这里省略了构造带ε动作的有限自动机的操作，然后用状态树构造与该ＮＦＡ等价的简化ＤＦＡ．这个算法在计算机上已实现，并且对输入的任意正则表达式，都可以输出等价于正则表达式的简化ＤＦＡ．该算法可以用于某些离散信息处理系统的设计与分析．

An algorithm for constructing the simplified DFA(Deterministic Finite Automaton) is introduced,which is equivalent to a given regular expression. The first step constructs an NFA(Nondeterministic Finite Automaton) equivalent to the regular expression, where the operation for constructing finite automata with ε moves is omitted. Then the simplified DFA equivalent to the NFA is constructed by using state transition trees. The algorithm bas been realized by computer programming, and for any input regular expression, a simplified DFA equivalent to the regular expression is produced. The algorithm can be applied in the design and analysis of the system with discrete inputs and outputs.