用c++写一个输入任意DFA化简,并以状态转换图输出的代码
时间: 2024-02-24 14:54:08 浏览: 85
好的,以下是一个简单的C++代码示例,可以输入任意DFA,将其最小化,并以状态转换图输出:
```c++
#include <iostream>
#include <vector>
#include <queue>
#include <map>
#include <set>
using namespace std;
// 定义一个DFA状态
struct State {
int id; // 状态ID
bool isFinal; // 是否为终止状态
map<char, int> transitions; // 转移函数
};
// 定义一个最小化后的DFA状态
struct MinState {
set<int> ids; // 等价状态集合
bool isFinal; // 是否为终止状态
map<char, int> transitions; // 转移函数
};
// DFA最小化算法
vector<MinState> minimizeDFA(vector<State>& dfa) {
int n = dfa.size();
// 初始化划分
vector<set<int>> partition(2);
for (int i = 0; i < n; i++) {
if (dfa[i].isFinal) {
partition[0].insert(i);
} else {
partition[1].insert(i);
}
}
vector<vector<int>> partitions(2, vector<int>(n));
partitions[0] = vector<int>(partition[0].begin(), partition[0].end());
partitions[1] = vector<int>(partition[1].begin(), partition[1].end());
// 记录当前划分是否变化
bool changed = true;
while (changed) {
changed = false;
// 对于每个字符进行划分
for (char c = 'a'; c <= 'z'; c++) {
vector<set<int>> newPartition;
for (auto& p : partition) {
set<int> newSet;
// 对于每个状态,找到它的转移状态
for (int i : p) {
if (dfa[i].transitions[c] != -1) {
newSet.insert(dfa[i].transitions[c]);
}
}
// 将转移状态相同的状态合并到同一个集合中
bool found = false;
for (auto& q : newPartition) {
if (q == newSet) {
found = true;
break;
}
}
if (!found) {
newPartition.push_back(newSet);
}
}
if (newPartition.size() > partition.size()) { // 划分有变化
changed = true;
partition = newPartition;
// 更新划分后的状态
for (int i = 0; i < newPartition.size(); i++) {
for (int j : newPartition[i]) {
partitions[i][j] = i;
}
}
}
}
}
// 构造最小化DFA
vector<MinState> minDFA(partition.size());
for (int i = 0; i < partition.size(); i++) {
set<int> ids = partition[i];
// 设置状态是否为终止状态
bool isFinal = false;
for (int j : ids) {
if (dfa[j].isFinal) {
isFinal = true;
break;
}
}
// 构造等价状态集合
set<char> symbols;
for (int j : ids) {
for (auto& p : dfa[j].transitions) {
symbols.insert(p.first);
}
}
// 构造转移函数
for (char c : symbols) {
int nextState = partitions[i][*ids.begin()]; // 找到任意一个状态的等价状态
for (int j : ids) {
if (dfa[j].transitions[c] != -1) {
nextState = partitions[i][dfa[j].transitions[c]];
break;
}
}
minDFA[i].transitions[c] = nextState;
}
minDFA[i].ids = ids;
minDFA[i].isFinal = isFinal;
}
return minDFA;
}
// 将DFA状态转换为字符串
string stateToString(int id, bool isFinal) {
string s = "q" + to_string(id);
if (isFinal) {
s = "*" + s;
}
return s;
}
// 输出状态转换图
void printTransitionGraph(vector<MinState>& dfa) {
cout << "digraph G {\n";
cout << " rankdir=LR;\n";
cout << " node [shape=circle];\n";
// 输出状态节点
for (int i = 0; i < dfa.size(); i++) {
cout << " " << stateToString(i, dfa[i].isFinal) << ";\n";
}
// 输出转移边
for (int i = 0; i < dfa.size(); i++) {
for (auto& p : dfa[i].transitions) {
cout << " " << stateToString(i, dfa[i].isFinal) << " -> " << stateToString(p.second, dfa[p.second].isFinal) << " [label=\"" << p.first << "\"];\n";
}
}
cout << "}\n";
}
int main() {
int n;
cin >> n;
// 输入DFA状态和转移函数
vector<State> dfa(n);
for (int i = 0; i < n; i++) {
dfa[i].id = i;
cin >> dfa[i].isFinal;
for (char c = 'a'; c <= 'z'; c++) {
int nextState;
cin >> nextState;
dfa[i].transitions[c] = nextState;
}
}
// 最小化DFA并输出状态转换图
vector<MinState> minDFA = minimizeDFA(dfa);
printTransitionGraph(minDFA);
return 0;
}
```
你可以输入DFA的状态数、终止状态以及转移函数,然后该代码会输出最小化后的DFA的状态转换图。希望这可以帮助到你!
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