我正在使用此方法在此自动机模拟器上从状态移动到下一个：
public void processString (String string){
StringBuilder stepString= new StringBuilder (string);
int actualStateIntIndex;
System.out.println("THE FOUND INITIAL ONE IS "+ theInitialStateIntIndex);
State firstState = allStates.get(theInitialStateIntIndex);
actualState = firstState;
while (stepString.length()>0){
Character characterToProcess = stepString.charAt(0);
stepString.deleteCharAt(0);
State nextState;
nextState = ((State)actualState.get(characterToProcess)); // pasa al siguiente State
actualState = nextState;
actualStateIntIndex=allStates.indexOf(actualState);
System.out.println("the actual state for " + stepString + " is " + actualStateIntIndex);
if ((actualState.isFinal==true) && (stepString.length()==0))
{
System.out.println("THE STRING " + string + " IS ACCEPTED AT STATE " + actualStateIntIndex );
}
else if (stepString.length()==0 && (actualState.isFinal==false)){
System.out.println("THE STRING " + string + " IS REJECTED AT STATE " + actualStateIntIndex);
}
}
}
下面：
State nextState;
nextState = ((State)actualState.get(characterToProcess));
我可能做错了什么，但我不明白。
自动机总是卡在状态0上，虽然StringBuilder正在被正确处理，为什么？
这是完整的代码：
package afd;
import java.io.*;
import java.util.*;
/**
*
* @author Administrator
*/
public class Main {
/**
* @param args the command line arguments
*/
public static void main(String[] args) throws IOException {
// TODO code application logic here
FileReader fr = new FileReader("E://Documents and Settings//Administrator//My Documents//NetBeansProjects//AFD//src//afd//dfa.in");
BufferedReader br = new BufferedReader(fr);
String firstLine= br.readLine();
String [] firstLineSplitted = firstLine.split(" ");
/*debug*/
//System.out.println("firstLine is " + firstLine);
int numberOfTestCases = Integer.parseInt(firstLine);
for (int indexOfTestCases =0; indexOfTestCases < numberOfTestCases; indexOfTestCases++ ){
int aux;
System.out.println("Case Number " + (aux = indexOfTestCases+1));
String caseStartLine = br.readLine();
/*debug*/
//System.out.println("caseStarLine is " + caseStartLine);
String [] caseStartLineSplitted = caseStartLine.split(" ");
int numberOfStates;
int numberOfAlphabetSymbols;
int numberOfFinalStates;
numberOfStates = Integer.parseInt(caseStartLineSplitted[0]);
numberOfAlphabetSymbols = Integer.parseInt(caseStartLineSplitted[1]);
numberOfFinalStates = Integer.parseInt(caseStartLineSplitted[2]);
Automaton automaton = new Automaton();
automaton.setAllStates(numberOfStates);
// automaton.size = numberOfStates;
// automaton.numberOfAlphabetSymbols = numberOfAlphabetSymbols;
// automaton.numberOfFinalStates = numberOfFinalStates;
//Automaton a = new Automaton(numberOfStates);
String alphabetLine = br.readLine();
System.out.println("alphabetLine is " + alphabetLine);
automaton.setAlphabet (alphabetLine);
// automaton.alphabetSymbols =new StringBuffer(alphabetLine);
for (int indexOfStates = 0; indexOfStates < numberOfStates; indexOfStates++){
String transitionsLine = br.readLine();
/*debug*/
System.out.println("for the state " + indexOfStates + " transitionsLine is " + transitionsLine);
automaton.setTransitions(indexOfStates,transitionsLine);
/*String [] ijLineSplitted = ijLine.split(" ");
int i = Integer.parseInt(ijLineSplitted[0]);
int j = Integer.parseInt(ijLineSplitted[1]);
*/
}
String finalStatesLine = br.readLine();
/*debug*/
System.out.println("finalStatesLine is " + finalStatesLine);
String finalStatesLineSplitted [] = finalStatesLine.split(" ");
automaton.markFinalStates(finalStatesLineSplitted);
String initialStateAndNumberOfStringsLine = br.readLine();
/*debug*/
//System.out.println("initialStateAndNumberOfStringsLine is " +initialStateAndNumberOfStringsLine);
String [] splittedInitialStateLine = initialStateAndNumberOfStringsLine.split(" ");
int initialState = Integer.parseInt(splittedInitialStateLine[0]);
int numberOfStrings = Integer.parseInt(splittedInitialStateLine[1]);
automaton.markInitialState(initialState);
for (int stringIndex =0; stringIndex<numberOfStrings; stringIndex++){
String stringToProcess = br.readLine();
/*debug*/
System.out.println("stringToProcess is " + stringToProcess);
automaton.processString(stringToProcess);
}
}
}
}
class State extends HashMap<Character, State>{
boolean isFinal;
boolean isInitial;
int stateId;
State () {
isInitial=false;
isFinal = false;
}
public boolean equals (Object o){
boolean isEqual = false;
State compare = (State)o;
if ((compare.stateId)==this.stateId)
{
return true;
}
return isEqual;
}
public int hashCode() {
int theHashCode = stateId%7;
return theHashCode;
}
}
class Automaton{
List <State> allStates;
//private List<State> finalStates;
int theInitialStateIntIndex;
State actualState;
char [] alphabet;
Automaton() {
allStates = new ArrayList<State>();
}public void setAllStates (int numberOfStates) {
for (int i =0; i <numberOfStates; i++) {
State newState = new State();
newState.stateId = i;
allStates.add(newState);
}
}
public void setAlphabet (String alphabetLine){
alphabet = alphabetLine.toCharArray();
}
public void markFinalStates (String [] finalStates){
for (int index =0; index<finalStates.length; index++) {
int aFinalStateId = Integer.parseInt(finalStates[index]);
State aFinalState = allStates.get(aFinalStateId);
aFinalState.isFinal = true;
allStates.add(aFinalStateId, aFinalState);
/*DEBUG*/
aFinalState = allStates.get(aFinalStateId);
if ((aFinalState.isFinal)==true)
System.out.println("THE STATE " + aFinalStateId + " IS MARKED AS FINAL");
}
}
public void markInitialState (int initialStateId) {
State theInitialState = allStates.get(initialStateId);
theInitialState.isInitial=true;
allStates.add(initialStateId, theInitialState);
theInitialStateIntIndex = initialStateId;
/*DEBUG*/
System.out.println("THE INITIAL STATE ID IS " + initialStateId);
theInitialState = allStates.get(initialStateId);
if ((theInitialState.isInitial)==true)
System.out.println("THE STATE " + initialStateId + " IS MARKED AS INITIAL");
}
public void setTransitions(int stateId, String transitionsLine){
State theOneToChange = allStates.get(stateId);
String [] statesToReachStringSplitted = transitionsLine.split(" ");
for (int symbolIndex=0; symbolIndex<statesToReachStringSplitted.length;symbolIndex++){
int reachedState= Integer.parseInt(statesToReachStringSplitted[symbolIndex]);
theOneToChange.put(alphabet[symbolIndex],allStates.get(reachedState));
System.out.println("THE STATE " + stateId + " REACHES THE STATE " + reachedState + " WITH THE SYMBOL " + alphabet[symbolIndex]);
}
allStates.add(stateId, theOneToChange);
}
public int findInitialState(){
int index =0;
cycle: for (; index<allStates.size(); index++){
State s = allStates.get(index);
if (s.isInitial==true) {
break cycle;
}
} return index;
}
public void processString (String string)
{
StringBuilder stepString= new StringBuilder (string);
int actualStateIntIndex;
System.out.println("THE FOUND INITIAL ONE IS "+ theInitialStateIntIndex);
State firstState = allStates.get(theInitialStateIntIndex);
actualState = firstState;
while (stepString.length()>0){
Character characterToProcess = stepString.charAt(0);
stepString.deleteCharAt(0);
State nextState;
nextState = ((State)actualState.get(characterToProcess)); // pasa al siguiente State
actualState = nextState;
actualStateIntIndex=allStates.indexOf(actualState);
System.out.println("the actual state for " + stepString + " is " + actualStateIntIndex);
if ((actualState.isFinal==true) && (stepString.length()==0))
{
System.out.println("THE STRING " + string + " IS ACCEPTED AT STATE " + actualStateIntIndex );
}
else if (stepString.length()==0 && (actualState.isFinal==false)){
System.out.println("THE STRING " + string + " IS REJECTED AT STATE " + actualStateIntIndex);
}
}
}
}
这是输入文件：
4
3 2 1
ab
1 0
2 0
2 0
2
0 3
abaa
aab
aba
3 3 2
ade
0 1 2
1 2 0
2 1 0
1 2
2 2
a
de
3 2 1
ab
1 0
2 0
2 0
2
0 3
abaa
aab
aba
3 3 2
ade
0 1 2
1 2 0
2 1 0
1 2
2 2
a
de
编辑：这里我将解释此输入文件的格式
第一行代表测试用例的数量。
每个测试用例以3个整数开始，第一个是自动机的状态数，接下来是字母表中符号的数量，然后是最终状态的数量。
下一行是字母表。符号一起出现。
然后有许多行等于描述转换函数的状态数。这组线的第一行表示自动机中第一个状态的转换函数（qo），第一个元素表示当字母表中的第一个符号进入此状态时达到的状态，依此类推。我从最初的问题陈述中理解这一点很困难。这是我最容易看到它的方式：
行：
1 0
2 0
2 0
等于：
AlphabetSymbol0 AlphabetSymbol1
State0 State1 State0
State1 State2 State0
State2 State2 State0
然后有一条线说明哪个是自动机的最终状态。
然后是一行，说明哪个是初始状态以及将有多少输入字符串。
然后输入带有输入字符串的行。
该程序的输出应为：
C
ase Number 1
alphabetLine is ab
for the state 0 transitionsLine is 1 0
THE STATE 0 REACHES THE STATE 1 WITH THE SYMBOL a
THE STATE 0 REACHES THE STATE 0 WITH THE SYMBOL b
for the state 1 transitionsLine is 2 0
THE STATE 1 REACHES THE STATE 2 WITH THE SYMBOL a
THE STATE 1 REACHES THE STATE 0 WITH THE SYMBOL b
for the state 2 transitionsLine is 2 0
THE STATE 2 REACHES THE STATE 2 WITH THE SYMBOL a
THE STATE 2 REACHES THE STATE 0 WITH THE SYMBOL b
finalStatesLine is 2
THE STATE 2 IS MARKED AS FINAL
THE INITIAL STATE ID IS 0
THE STATE 0 IS MARKED AS INITIAL
stringToProcess is abaa
THE FOUND INITIAL ONE IS 0
the actual state for baa is 0
the actual state for aa is 0
the actual state for a is 0
the actual state for is 0
**THE STRING abaa IS ACCEPTED AT STATE 2**
stringToProcess is aab
THE FOUND INITIAL ONE IS 0
the actual state for ab is 0
the actual state for b is 0
the actual state for is 0
**THE STRING aab IS REJECTED AT STATE 0**
stringToProcess is aba
THE FOUND INITIAL ONE IS 0
the actual state for ba is 0
the actual state for a is 0
the actual state for is 0
**THE STRING aba IS ACCEPTED AT STATE 1**
Case Number 2
alphabetLine is ade
for the state 0 transitionsLine is 0 1 2
THE STATE 0 REACHES THE STATE 0 WITH THE SYMBOL a
THE STATE 0 REACHES THE STATE 1 WITH THE SYMBOL d
THE STATE 0 REACHES THE STATE 2 WITH THE SYMBOL e
for the state 1 transitionsLine is 1 2 0
THE STATE 1 REACHES THE STATE 1 WITH THE SYMBOL a
THE STATE 1 REACHES THE STATE 2 WITH THE SYMBOL d
THE STATE 1 REACHES THE STATE 0 WITH THE SYMBOL e
for the state 2 transitionsLine is 2 1 0
THE STATE 2 REACHES THE STATE 2 WITH THE SYMBOL a
THE STATE 2 REACHES THE STATE 1 WITH THE SYMBOL d
THE STATE 2 REACHES THE STATE 0 WITH THE SYMBOL e
finalStatesLine is 1 2
THE STATE 1 IS MARKED AS FINAL
THE STATE 2 IS MARKED AS FINAL
THE INITIAL STATE ID IS 2
THE STATE 2 IS MARKED AS INITIAL
stringToProcess is a
THE FOUND INITIAL ONE IS 2
the actual state for is 0
**THE STRING a IS ACCEPTED AT STATE 2**
stringToProcess is de
THE FOUND INITIAL ONE IS 2
the actual state for e is 0
the actual state for is 0
**THE STRING de IS REJECTED AT STATE 0**
我错了用粗体写的所有行。
我得到了：
Case Number 1
THE STRING abaa IS ACCEPTED AT STATE 0
THE STRING aab IS ACCEPTED AT STATE 0
THE STRING aba IS ACCEPTED AT STATE 0
Case Number 2
THE STRING a IS ACCEPTED AT STATE 0
THE STRING de IS ACCEPTED AT STATE 0
我的自动机正在接受所有事情并陷入状态0，为什么？
答案 0 :(得分：2)
我很确定问题是State需要覆盖.equals（Object）和.hashCode（）。我相信allStates是List<State>并且在该列表上调用get（State）必须重写equals。
答案 1 :(得分：1)
嗯，首先，processState方法似乎根本不更新自动机的currentState字段。事实上，你似乎没有在任何地方修改它。
如果你解释一下你做得更好的话会有所帮助。您刚刚转储了许多未注释的源代码并说“它会卡在状态0”，即使我们不知道状态0是什么或者如何检测到这种情况。我是猜测 currentState指向这个，虽然State实例也没有数字，所以很难知道从哪里开始分析这个......
至少，提供两位信息（虽然更多会更好）：