用文法G[S]：→aU|bV U→bV|aQ V→aU|bQ Q→aQ|bQ|e构成DFA模拟程序，要求使用C#

以下是使用C#实现文法G[S]模拟DFA的代码：

using System;
using System.Collections.Generic;

class DFA
{
    private HashSet<int> states;
    private HashSet<char> alphabet;
    private Dictionary<Tuple<int, char>, int> transitions;
    private int startState;
    private HashSet<int> acceptStates;

    public DFA(HashSet<int> states, HashSet<char> alphabet, Dictionary<Tuple<int, char>, int> transitions,
        int startState, HashSet<int> acceptStates)
    {
        this.states = states;
        this.alphabet = alphabet;
        this.transitions = transitions;
        this.startState = startState;
        this.acceptStates = acceptStates;
    }

    public bool Run(string inputString)
    {
        int currentState = startState;
        foreach (char symbol in inputString)
        {
            if (!alphabet.Contains(symbol))
            {
                return false;
            }
            Tuple<int, char> transition = new Tuple<int, char>(currentState, symbol);
            if (transitions.ContainsKey(transition))
            {
                currentState = transitions[transition];
            }
            else
            {
                return false;
            }
        }
        return acceptStates.Contains(currentState);
    }
}

class Program
{
    static void Main(string[] args)
    {
        HashSet<int> states = new HashSet<int>{ 0, 1, 2, 3 };
        HashSet<char> alphabet = new HashSet<char>{ 'a', 'b' };
        Dictionary<Tuple<int, char>, int> transitions = new Dictionary<Tuple<int, char>, int>
        {
            { new Tuple<int, char>(0, 'a'), 1 },
            { new Tuple<int, char>(0, 'b'), 2 },
            { new Tuple<int, char>(1, 'a'), 3 },
            { new Tuple<int, char>(1, 'b'), 2 },
            { new Tuple<int, char>(2, 'a'), 1 },
            { new Tuple<int, char>(2, 'b'), 3 },
            { new Tuple<int, char>(3, 'a'), 3 },
            { new Tuple<int, char>(3, 'b'), 3 }
        };
        int startState = 0;
        HashSet<int> acceptStates = new HashSet<int>{ 1, 3 };

        DFA dfa = new DFA(states, alphabet, transitions, startState, acceptStates);

        Console.WriteLine(dfa.Run("abab")); // true
        Console.WriteLine(dfa.Run("baba")); // true
        Console.WriteLine(dfa.Run("abb")); // false
    }
}

在代码中，我们定义了DFA类来表示模拟的有限状态自动机。构造函数接收五个参数：状态集合、字母表、转移字典、起始状态和接受状态集合。Run方法接收一个输入字符串并返回一个布尔值，表示该字符串是否被DFA接受。

在Main函数中，我们使用文法G[S]构造了一个DFA，然后使用该DFA运行了三个不同的输入字符串，并输出了结果。

注意：本代码是基于输入文法G[S]实现的。如果输入的文法不同，需要相应地修改代码。