用c++实现输入任意给定的DFA,化简,并以状态转换图方式输出。
时间: 2024-02-19 09:57:56 浏览: 72
好的,这是一个比较复杂的问题,需要进行多步操作,我会尽我所能地为您解答。
1. 输入任意给定的DFA
首先,我们需要定义一个DFA类,来表示一个DFA。DFA类包含以下成员变量:
- int n:表示DFA中状态的数量。
- int m:表示DFA中字符集的大小。
- vector<vector<int>> g:表示DFA中的状态转移表,g[i][j]表示从状态i经过字符集中第j个字符转移到的状态。
- vector<bool> is_terminal:表示DFA中每个状态是否为终止状态。
- vector<bool> is_start:表示DFA中每个状态是否为起始状态。
接下来,我们可以使用如下代码来输入一个DFA:
```c++
#include <iostream>
#include <vector>
using namespace std;
class DFA {
public:
int n, m;
vector<vector<int>> g;
vector<bool> is_terminal, is_start;
};
DFA input_DFA() {
DFA dfa;
cin >> dfa.n >> dfa.m;
dfa.g.resize(dfa.n, vector<int>(dfa.m));
dfa.is_terminal.resize(dfa.n);
dfa.is_start.resize(dfa.n);
for (int i = 0; i < dfa.n; i++) {
for (int j = 0; j < dfa.m; j++) {
cin >> dfa.g[i][j];
}
cin >> dfa.is_terminal[i];
cin >> dfa.is_start[i];
}
return dfa;
}
int main() {
DFA dfa = input_DFA();
// do something with dfa
return 0;
}
```
2. 化简DFA
接下来,我们需要对输入的DFA进行化简。化简DFA的主要思想是将等价的状态合并成一个状态。具体来说,我们可以使用Hopcroft算法来实现DFA的最小化。Hopcroft算法的时间复杂度为O(nlogn),非常高效。
下面是使用Hopcroft算法来化简DFA的代码:
```c++
vector<vector<int>> hopcroft(const DFA& dfa) {
vector<vector<int>> buckets(dfa.n + 1);
vector<int> p(dfa.n), cnt(dfa.n);
for (int i = 0; i < dfa.n; i++) {
p[i] = i;
cnt[i] = (dfa.is_terminal[i] ? 1 : 0);
buckets[cnt[i]].push_back(i);
}
vector<vector<int>> g(dfa.n, vector<int>(dfa.m));
for (int i = 0; i < dfa.n; i++) {
for (int j = 0; j < dfa.m; j++) {
g[i][j] = buckets[p[dfa.g[i][j]]][0];
}
}
vector<bool> vis(dfa.n), in_L(dfa.n);
vector<int> L;
vis[0] = true;
L.push_back(0);
while (!L.empty()) {
int x = L.back();
L.pop_back();
in_L[x] = false;
for (int j = 0; j < dfa.m; j++) {
int y = g[x][j];
if (!vis[y]) {
vis[y] = true;
L.push_back(y);
in_L[y] = true;
}
}
}
for (int i = 0; i < dfa.n; i++) {
if (!vis[i]) {
cnt[p[i]]--;
buckets[cnt[p[i]]].push_back(i);
}
}
vector<vector<int>> new_g(dfa.n, vector<int>(dfa.m));
vector<int> new_p(dfa.n);
int new_n = 0;
for (int i = 0; i <= dfa.n; i++) {
for (int j : buckets[i]) {
new_p[j] = new_n;
}
if (!buckets[i].empty()) {
new_n++;
}
}
for (int i = 0; i < dfa.n; i++) {
for (int j = 0; j < dfa.m; j++) {
new_g[new_p[i]][j] = new_p[g[i][j]];
}
}
return new_g;
}
DFA minimize_DFA(const DFA& dfa) {
DFA new_dfa;
new_dfa.n = dfa.n;
new_dfa.m = dfa.m;
new_dfa.g = hopcroft(dfa);
new_dfa.is_terminal.resize(dfa.n);
new_dfa.is_start.resize(dfa.n);
for (int i = 0; i < dfa.n; i++) {
new_dfa.is_terminal[new_dfa.g[i][0]] |= dfa.is_terminal[i];
new_dfa.is_start[new_dfa.g[i][0]] |= dfa.is_start[i];
}
new_dfa.n = 0;
vector<int> pos(dfa.n);
for (int i = 0; i < dfa.n; i++) {
if (new_dfa.g[i] == new_dfa.g[0]) {
pos[i] = new_dfa.n++;
}
}
new_dfa.g.resize(new_dfa.n);
for (int i = 0; i < dfa.n; i++) {
for (int j = 0; j < dfa.m; j++) {
int x = pos[i], y = pos[dfa.g[i][j]];
if (new_dfa.g[x].empty() || new_dfa.g[x].back() != y) {
new_dfa.g[x].push_back(y);
}
}
}
return new_dfa;
}
```
3. 输出状态转换图
最后,我们需要将化简后的DFA以状态转换图的形式输出。我们可以使用Graphviz工具来生成状态转换图。Graphviz是一个开源的图形可视化工具,可以根据输入的DOT语言文件生成各种类型的图形。
下面是使用Graphviz来生成状态转换图的代码:
```c++
void output_DFA(const DFA& dfa) {
cout << "digraph G {" << endl;
for (int i = 0; i < dfa.n; i++) {
cout << " " << i;
if (dfa.is_start[i]) {
cout << " [style=filled, shape=circle, color=green]";
} else if (dfa.is_terminal[i]) {
cout << " [style=filled, shape=circle, color=red]";
} else {
cout << " [shape=circle]";
}
cout << ";" << endl;
}
for (int i = 0; i < dfa.n; i++) {
for (int j = 0; j < dfa.m; j++) {
int k = dfa.g[i][j];
cout << " " << i << " -> " << k << " [label=\"" << j << "\"];" << endl;
}
}
cout << "}" << endl;
}
int main() {
DFA dfa = input_DFA();
DFA new_dfa = minimize_DFA(dfa);
output_DFA(new_dfa);
return 0;
}
```
这样,我们就完成了输入任意给定的DFA,化简,并以状态转换图方式输出的任务。
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