/**

使用NFA模拟的模式匹配

*/

public boolean recognizes(String txt){

Bag<Integer> pc = new Bag<Integer>();

DirectedDFS dfs = new DirectedDFS(g, 0); // g? 起点可达

for (int v = 0; v < g.V(); v++){

if (dfs.marked(v)){

pc.add(v);

}

}

for (int i = 0; i < txt.length(); i++){

Bag<Integer> match = new Bag<Integer>();

for (int v : pc){

if (v < M){

if (re[v] == txt.charAt(i) || re[v] == '.'){

match.add(v+1);

}

}

}

pc = new Bag<Integer>();

dfs = new DirectedDFS(g, match); // 多点可达

for (int v = 0; v < G.V(); v++){

if (dfs.marked(v)){

pc.add(v);

}

}

}

for (int v : pc){

if (v == M){

return true;

}

}

return false;

}