We have a program that compares thousands of pairs of Students by checking each field of the Student and counting the diffs:
class Student{
String name;
String address;
String biologyCourse;
.....
// about 100 other fields
}
And the counter POJO class:
class Counters{
long bothStudentsHaveName;
long onlyLeftHasName;
long onlyRightHasName;
......
// number of fields in Student * 3 (both, only left, only right)
}
Our compare function accepts 2 students plus the counters object and needs to scan the fields and update the relevant counters:
public void compareStudents(Student left, Student right, Counters counters){
if (!StringUtils.isEmpty(left.name) && !StringUtils.isEmpty(right.name) ){
counters.bothStudentsHaveName++;
} else if (StringUtils.isEmpty(left.name) && !StringUtils.isEmpty(right.name)){
counters.onlyRightHasName++;
} else if (!StringUtils.isEmpty(left.name) && StringUtils.isEmpty(right.name))){
counters.onlyLeftHasName++;
}
/// and now??
}
At this point, we can add 100s more triplets of if/else like the above - but we believe there should be a much easier way to do that.
Reflection can be an option or maybe X dimensions arrays, but can we somehow write the code so the comparison and counting will be much more generic?
I have solved your problem with one single loop. But here I'm assuming that naming convention for all the fields will be the same as described in your question. Here I am dynamically accessing the Student fields and updating Counter fields accordingly. Here is the complete solution:
Solution Class:
public class Solution {
public void compareStudents(Student left, Student right, Counter counter) throws Exception {
for (Field field : Student.class.getDeclaredFields()) {
Object leftValue = field.get(left);
Object rightValue = field.get(right);
String fieldName = field.getName().substring(0, 1).toUpperCase() + field.getName().substring(1);
if(leftValue != null && rightValue != null) {
Field counterField = Counter.class.getDeclaredField("bothStudentsHave" + fieldName);
counterField.set(counter, (long) counterField.get(counter) + 1);
} else if (leftValue != null) {
Field counterField = Counter.class.getDeclaredField("onlyLeftHas" + fieldName);
counterField.set(counter, (long) counterField.get(counter) + 1);
} else if (rightValue != null) {
Field counterField = Counter.class.getDeclaredField("onlyRightHas" + fieldName);
counterField.set(counter, (long) counterField.get(counter) + 1);
}
}
}
}
Student Class:
class Student {
String name;
String address;
String biologyCourse;
}
Counter Class:
class Counter {
// name
long bothStudentsHaveName;
long onlyLeftHasName;
long onlyRightHasName;
// address
long bothStudentsHaveAddress;
long onlyLeftHasAddress;
long onlyRightHasAddress;
// biologyCourse
long bothStudentsHaveBiologyCourse;
long onlyLeftHasBiologyCourse;
long onlyRightHasBiologyCourse;
// ... and so on
#Override
public String toString() {
return "Counter{" + "\n" +
"\tbothStudentsHaveName = " + bothStudentsHaveName + "\n" +
"\t, onlyLeftHasName = " + onlyLeftHasName + "\n" +
"\t, onlyRightHasName = " + onlyRightHasName + "\n" +
"\t, bothStudentsHaveAddress = " + bothStudentsHaveAddress + "\n" +
"\t, onlyLeftHasAddress = " + onlyLeftHasAddress + "\n" +
"\t, onlyRightHasAddress = " + onlyRightHasAddress + "\n" +
"\t, bothStudentsHaveBiologyCourse = " + bothStudentsHaveBiologyCourse + "\n" +
"\t, onlyLeftHasBiologyCourse = " + onlyLeftHasBiologyCourse + "\n" +
"\t, onlyRightHasBiologyCourse = " + onlyRightHasBiologyCourse + "\n" +
'}';
}
}
Tester Class:
public class Tester {
public static void main(String[] args) throws Exception {
// Creating Dummy Variables
Student student1 = new Student();
student1.name = "Test";
student1.biologyCourse = "Yes";
Student student2 = new Student();
student2.name = "Test1";
student2.address = "abc street";
Counter counter = new Counter();
// Comparing Students
Solution solution = new Solution();
solution.compareStudents(student1, student2, counter);
// Printing Counter
System.out.println(counter);
}
}
Output:
Counter{
bothStudentsHaveName = 1
, onlyLeftHasName = 0
, onlyRightHasName = 0
, bothStudentsHaveAddress = 0
, onlyLeftHasAddress = 0
, onlyRightHasAddress = 1
, bothStudentsHaveBiologyCourse = 0
, onlyLeftHasBiologyCourse = 1
, onlyRightHasBiologyCourse = 0
}
If you keep repreating the same basic pattern of fields, then consider extracting that into a class. For example introduce a FieldComparison class that looks a little like this:
public class FieldComparisonCounter {
public int bothHave;
public int onlyLeftHas;
public int onlyRightHas;
// constructor, getters, setters left as an exercise for the reader
}
Then have a Map<String,FieldComparisonCounter> counters somewhere and a method like this:
public void compareField(String fieldName, String leftValue, String rightValue) {
FieldComparisonCounter counter = counters.get(fieldName);
if (counter == null) {
counter = new FieldComparisonCounter();
counters.put(fieldName, counter);
}
boolean leftHas = !StringUtils.isEmpty(leftValue);
boolean rightHas = !StringUtils.isEmpty(rightValue);
if (leftHas && rightHas) {
counter.bothHave++;
} else if (leftHas) {
counter.onlyLeftHas++;
} else if (rightHas) {
counter.onlyRightHas++;
}
}
Then adding a new field comparison is as simple as calling
compareField("name", left.name, right.name);
Related
I've worked on the project in my school and stuck with an error. I cannot run this code since it has an error 'randA2 is already defined in method main(String[])' How can I fix it?
String [] A = {"Russia", "Saudi_Arabia", "Egypt", "Uruguay"};
int A1 = A.length;
int randA1 = (int)(Math.random()*A1);
int randA2 = (int)(Math.random()*A1);
int randA3 = (int)(Math.random()*A1);
int randA4 = (int)(Math.random()*A1);
while(randA1 == randA2) {
int randA2 = (int)(Math.random()*A1);
}
while(randA1 == randA3) {
int randA3 = (int)(Math.random()*A1);
}
while(randA2 == randA3) {
int randA3 = (int)(Math.random()*A1);
}
while(randA1 == randA4) {
int randA4 = (int)(Math.random()*A1);
}
while(randA2 == randA4) {
int randA4 = (int)(Math.random()*A1);
}
while(randA3 == randA4) {
int randA4 = (int)(Math.random()*A1);
}
String AnnounceA1 = A[randA1] +" " + "VS" + " " + A[randA2];
System.out.println(AnnounceA1);
String AnnounceA2 = A[randA3] +" " + "VS" + " " + A[randA4];
System.out.println(AnnounceA2);
I would like to use another way to solve your problem, all you need is :
String[] contries = {"Russia", "Saudi_Arabia", "Egypt", "Uruguay"};
Collections.shuffle(Arrays.asList(contries));
String announceA1 = contries[0] + " VS " + contries[1];
System.out.println(announceA1);
String announceA2 = contries[2] + " VS " + contries[3];
System.out.println(announceA2);
If you want to reassign a new value to a variable in Java, then you don't need to declare its type again. So your first while loop should look like this:
while (randA1 == randA2) {
randA2 = (int)(Math.random()*A1);
}
But besides this, your code has a logical problem, and it won't actually generate 4 unique random numbers. Actually, if you control which numbers you accept, they aren't really random. I would go with this version:
String[] teams = { "Russia", "Saudi_Arabia", "Egypt", "Uruguay" };
Set<Integer> rands = new HashSet<>();
while (rands.size() < teams.length) {
rands.add((int)(Math.random()*teams.length));
}
String AnnounceA1 = teams[rands[0]] +" " + "VS" + " " + teams[rands[1]];
System.out.println(AnnounceA1);
String AnnounceA2 = teams[rands[2]] +" " + "VS" + " " + teams[rands[3]];
System.out.println(AnnounceA2);
The strategy in my suggested version of your code is using a set to hold 4 random integers (which is the number of teams in your example). It is a property of sets that every entry has to be unique. So, if we iterate this set, adding random integers, we will eventually end up with 4 unique random integers. Then, we can use them to choose team names to display in your output message.
You redefine your vars inside the while loops.
Ommit the int declaration iside the while loops:
...
while(randA1 == randA2) {
randA2 = (int)(Math.random()*A1);
}
while(randA1 == randA3) {
randA3 = (int)(Math.random()*A1);
}
...
Java is a type safety language. This is different to for example JavaScript. Inside JavaScipt the JIT (Just in time compiler) would not complain, because it is allowed to redefine variables, event if the type is changing.
I'm trying to get the hang of queues by making a very simple program that simulates a checkout line. For some reason my custom dequeue function (using a linkedlist's removeFirst()) wont actually delete stuff in the queue.
Heres the CustomerQueue Class
public class CustomerQueue<E> {
private LinkedList<E> list = new LinkedList<>();
public void enqueue(E e) { list.addLast(e); }
public E dequeue() { return list.removeFirst(); }
public int size() { return list.size(); }
public E element() { return list.getFirst(); }
#Override
public String toString() { return "Queue: " + list.toString(); }
}
Here is my main:
public static void main(String[] args) {
CustomerQueue<Customer> queue = new CustomerQueue<>();
final int totalTime = 720;
int totalServiced = 0;
int totalQueued = 0;
int totalArrived = 1;
int maxQueuedAtOnce = 0;
Customer next = new Customer();
queue.enqueue(next);
System.out.println(next.getATime() + " <-- ATIME STIME --> " + next.getSTime());
for (int minute = 0; minute < totalTime; minute++) {
System.out.println("-- Minute " + (minute + 1) + " ---------");
if (queue.element().getSTime() == 0) {
totalServiced++;
System.out.println("Current customer (" + queue.dequeue() + ") finished being serviced. (Removed)");
//queue.dequeue();
}
if (next.getATime() == 0) {
System.out.println("Customer ID=" + next.getID() + " has arrived.");
queue.enqueue(next);
System.out.println("Customer ID=" + next.getID() + " in queue.");
next = new Customer();
System.out.println("New Customer generated. ID=" + next.getID() + " ATIME: " + next.getATime() + " STIME: " + next.getSTime());
totalArrived++;
totalQueued++;
}
System.out.println("Customer ID=" + next.getID() + " arrival ticked down.");
next.tickArrivalDown();
queue.element().tickServiceDown();
System.out.println("Current queue customer ID=" + next.getID() + " ticked down.");
if (queue.size() > maxQueuedAtOnce)
maxQueuedAtOnce = queue.size();
}
System.out.println("Total Customers Generated " + next.getNumCustomers());
System.out.println("Total Customers Serviced: " + totalServiced);
System.out.println("Total Customers Arrived: " + totalArrived);
System.out.println("Maximum Customers Queued: " + maxQueuedAtOnce);
System.out.println(queue.element());
}
And of course the Customer Class:
public class Customer {
private int serviceTime;
private int arrivalTime;
private static int numCustomers = 0;
private int ID;
public int getSTime() { return serviceTime; }
public void setSTime(int t) { serviceTime = t; }
public int getATime() { return arrivalTime; }
public void setATime(int t) { arrivalTime = t; }
public int getID() { return ID; }
public static int getNumCustomers() { return numCustomers; }
Customer() {
serviceTime = (int) (Math.random()*3 + 1);
arrivalTime = (int) (Math.random()*3 + 1);
ID = ++numCustomers;
}
public void tickServiceDown() { serviceTime--; }
public void tickServiceUp() { serviceTime++; }
public void tickArrivalDown() { arrivalTime--; }
public void tickArrivalUp() { arrivalTime++; }
#Override
public String toString() {
return "ID: " + ID + " ArrivalTime: " + arrivalTime + " ServiceTime: " + serviceTime;
}
}
The Customer class I have setup generates its own arrival time and completion time when a Customer is instantiated. Basically at the end of the loop, the next customer's arrival time ticks down and the current customer's service time ticks down. When the current customer's service time hits 0, it should dequeue/remove the first element in the LinkedList. For some reason it isnt removing it. Here is the post-loop output:
Total Customers Generated 358
Total Customers Serviced: 1
Total Customers Arrived: 358
Maximum Customers Queued: 357
ID: 1 ArrivalTime: 0 ServiceTime: -717
I'm totally stumped, no amount of googling has helped.
Looking at your output
ID: 1 ArrivalTime: 0 ServiceTime: -717
and ServiceTime being what is being returned in getSTime()
then as 0 != -717 I think the below will be fine
How about if (queue.element().getSTime() <= 0) {
I figured out the answer. The initial if statement:
if (queue.element().getSTime() == 0) needed to become if (queue.size() > 0 && queue.element().getSTime() == 0)
Also needed to make the queue.element().tickServiceDown(); enclosed with the following if-statement if (queue.size() > 0)
I made this code for extracting Polynomial coefficients and also evaluating equation in a point,and it is work.
but i want to modify that so the user can enter any shape of polynomial equation.
in my code you have to enter equation like this:
2*x^2+3*x^1+4
but i want :
2*x^5+1*x+6
also if there any term with same power , their coeffs must be added together.
Here is my code in java:
package Priest;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.List;
public class Equation {
private String Eq;
private final String[] C;
private int Deg;
private final String EqHolder;
public Equation(String Equation) {
this.Eq = Equation;
EqHolder = Equation;
Eq = Eq.replaceAll("[^0-9\\-\\.]+", " ");
Eq = Eq.replaceAll("-", " -");
this.C = Eq.split(" ");
}
public String SourceEquation() {
return EqHolder.toUpperCase().replaceAll("\\*", "").replaceAll("[a-zA-Z]", "\\*(X)").replaceAll("\\+", "\\ + ").replaceAll("\\-", "\\ - ");
}
public List<BigDecimal> CaptureCoeff() {
getDegree();
List<BigDecimal> Temp = new ArrayList<>();
for (String S : C) {
Temp.add(new BigDecimal(S));
}
int Location = Temp.indexOf(BigDecimal.valueOf(Deg));
List<BigDecimal> Coeffs = new ArrayList<>();
for (int Counter = Location - 1; Counter < Temp.size(); Counter += 2) {
Coeffs.add(Temp.get(Counter));
}
return Coeffs;
}
public int getDegree() {
int Degree = 0;
for (int Counter = 0; Counter < C.length; Counter += 2) {
if ((new Double(C[Counter])) != 0) {
Degree = new Integer(C[Counter + 1]);
this.Deg = Degree;
break;
}
}
return Degree;
}
public BigDecimal Evaluate(List<BigDecimal> Coefficients, double EvalPoint) {
BigDecimal Output = BigDecimal.ZERO;
for (int Index = 0; Index < Coefficients.size(); Index++) {
Output = Output.add(Coefficients.get(Index).multiply(BigDecimal.valueOf(EvalPoint).pow(Deg--)));
}
return Output;
}
}
and main class:
package Priest;
import java.math.RoundingMode;
public class MainClass {
public static void main(String[] args) {
long Start = System.nanoTime();
String Str = "3.1415x^5-12.6x^4+6x^3+12*x^2-6*x^1-0";
Equation E = new Equation(Str);
System.out.println("Equation is: " + E.SourceEquation());
System.out.println("Coefficients :" + E.CaptureCoeff());
System.out.println("Polynomial Degree: " + E.getDegree());
double Target = 47.784;
System.out.println("Equation # (X:" + Target + ")= " + E.Evaluate(E.CaptureCoeff(), Target).setScale(15, RoundingMode.HALF_UP));
System.out.println("Elapsed Time: " + String.format("%.20G", (System.nanoTime() - Start) / 1.0e6) + " ms.");
}
}
the output:
run:
Equation is: 3.1415*(X)^5 - 12.6*(X)^4 + 6*(X)^3 + 12*(X)^2 - 6*(X)^1 - 0
Coefficients :[3.1415, -12.6, 6, 12, -6, 0]
Polynomial Degree: 5
Equation # (X:47.784)= 717609084.382589022327914
Elapsed Time: 32.306242000000000000 ms.
BUILD SUCCESSFUL (total time: 0 seconds)
Let's go with the following equation String Str2 = "3.1415x^5+6x^2+12*x-5";
Here is the code that I have added upon your code in order to preprocess this equation and made it compatible to your actual logic so that It will treat it without any major change to your code.
To be totally accurate I had to change the following in your equation class:
public List<BigDecimal> CaptureCoeff() {
getDegree();
List<BigDecimal> Temp = new ArrayList<BigDecimal>();
for (String S : C) {
if (! "".equals(S.trim())) {
Temp.add(new BigDecimal(S));
}
}
So I have added the control to check that none of these S strings is trim - empty.
Here is my preprocessing code.
I have added a method called powerSplitt that allows to splitt the equation on the basis of the '^' char.
Then I created another method called generateNullCoeffPolynomeWithDegree that generate a monome in the form 0*X^k. And a similar one that generate all the similar intermediate monomes between the greater power and the lesser power
Example:
String str3 = generateAllNullCoeffPolynomesWithDegreeExclusiveBetween(5, 2);
System.out.println("all poly = " + str3);
will generate: all poly = 0*x^4+0*x^3
Then I created a buildPreProcessedPolynome that takes the initial equation and pre process it to produce one with the null monomes inside of it. And then I just gave it to your equation program and it could process it fine!!!
Here is the code and a call example all done in the MainClass
import java.math.RoundingMode;
import java.util.ArrayList;
import java.util.List;
public class MainClass {
private static List<String> workList = new ArrayList<String>();
public static void powerSplitt(String equationText) {
char[] charsList = equationText.toCharArray();
boolean foundTargetChar = false;
int index = 0;
for (int i = 0; i < charsList.length; i++) {
index = i;
if (charsList[i] == '^') {
foundTargetChar = true;
break;
}
}
if (foundTargetChar) {
workList.add(equationText.substring(0, index));
if (index +1 < equationText.length()) {
powerSplitt(equationText.substring(index+1));
} else {
workList.add(equationText);
return;
}
} else {
workList.add(equationText);
}
}
public static String generateNullCoeffPolynomeWithDegree(int degree) {
return "0*x^" + degree;
}
public static String generateAllNullCoeffPolynomesWithDegreeExclusiveBetween(int startDegree, int endDegree) {
if (startDegree-endDegree <= 1) {
return "";
}
int index = 0;
StringBuilder builder = new StringBuilder();
for (int i = startDegree -1; i > endDegree; i--) {
if (index > 0) {
builder.append("+");
}
builder.append(generateNullCoeffPolynomeWithDegree(i));
index++;
}
return builder.toString();
}
public static String buildPreProcessedPolynome(String initialEquationText) {
workList.clear();
powerSplitt(initialEquationText);
StringBuilder resultBuilder = new StringBuilder();
assert workList.size() >= 3;
resultBuilder.append(workList.get(0));
for (int i = 1; i <= workList.size()-2; i++) {
int actualPower = Integer.parseInt( workList.get(i).substring(0,1));
int nextFoundPower = Integer.parseInt( workList.get(i+1).substring(0,1));
System.out.print("actual power = " + actualPower + " and next power = " + nextFoundPower);
System.out.println();
String additionalPolyParts = generateAllNullCoeffPolynomesWithDegreeExclusiveBetween(actualPower, nextFoundPower);
resultBuilder.append("^" + actualPower);
resultBuilder.append("+");
resultBuilder.append(additionalPolyParts);
resultBuilder.append(workList.get(i).substring(1));
}
resultBuilder.append("^" + workList.get(workList.size()-1));
return resultBuilder.toString();
}
public static void main(String[] args) {
workList.clear();
String Str2 = "3.1415x^5+6x^2+12*x-5";
powerSplitt(Str2);
for (String part: workList) {
System.out.println("PART:" + part);
}
System.out.println("-----------------");
long Start = System.nanoTime();
String str3 = generateAllNullCoeffPolynomesWithDegreeExclusiveBetween(5, 2);
System.out.println("all poly = " + str3);
String preprocessed = buildPreProcessedPolynome(Str2);
System.out.println("preprocessed = " + preprocessed);
System.out.println();
Equation E = new Equation(preprocessed);
System.out.println("Equation is: " + E.SourceEquation());
System.out.println("Coefficients :" + E.CaptureCoeff());
System.out.println("Polynomial Degree: " + E.getDegree());
double Target = 47.784;
System.out.println("Equation # (X:" + Target + ")= " + E.Evaluate(E.CaptureCoeff(), Target).setScale(15, RoundingMode.HALF_UP));
System.out.println("Elapsed Time: " + String.format("%.20G", (System.nanoTime() - Start) / 1.0e6) + " ms.");
}
}
And here is the produced results (I haved added some System.out.println to check the results of my methods calls. I just noticed I have to take into account the last constant as a monome of type K*X^0, but I will leave that to you):
PART:3.1415x
PART:5+6x
PART:2+12*x-5
all poly = 0*x^4+0*x^3
actual power = 5 and next power = 2
preprocessed = 3.1415x^5+0*x^4+0*x^3+6x^2+12*x-5
Equation is: 3.1415*(X)^5 + 0*(X)^4 + 0*(X)^3 + 6*(X)^2 + 12*(X) - 5
Coefficients :[3.1415, 0, 0, 6, 12]
Polynomial Degree: 5
Equation # (X:47.784)= 782631805.485054892561514
Elapsed Time: 18,441978000000000000 ms.
In my program, I have three variables: when one of these variables reaches 100, it must appear the words "variable came first to the finish line."
How do I organize the arrival of the second and third variable, so they come out like this:
variable1-arrived first
variable2-finished second
variable3 finished third
Help!
public Corsa(String name)
{
this.name = name;
System.out.println("Start: " + name);
System.out.println("---------------");
}
public void run()
{
while(finita == false)
{
try
{
avanza = (int) (Math.random()*20+1);
percorso = percorso + avanza;
System.out.println(name + " has path " + percorso + " meters");
if(percorso < 100)
{
System.out.println("---------------");
sleep = (int) (Math.random()*20+1);
Thread.sleep(sleep);
}
else
{
System.out.println("---------------");
System.out.println("---------------");
System.out.println(name + " came in first");
finita = true;
}
}
catch(InterruptedException e){}
Thread.yield();
}
}
}
I haven't tested this (so it might not even compile), but something like the following should work:
public class myRace
{
private int distance = 100;
private float offset = 20;
public int runners[3];
public void run()
{
// Set all runners to 0
for ( int i = 0; i < runners.length; i++ )
runners[i] = 0;
// Run the race and stop when at least 1 runner has reached the distance...
boolean finished = false;
while ( !finished )
{
for ( int i = 0; i < runners.length; i++ )
{
runners[i] += (int)((Math.random() * offset) + 1);
if ( runners[i] >= distance ) finished = true;
}
}
// Race finished now sort the runners
TreeMap<String, int> ranking = new TreeMap<String, int>();
for ( int i = 0; i < runners.length; i++ )
{
// A TreeMap is sorted on its key, not the value!
// The runners number is tagged on, just in case two runners have finished on the same distance.
String sortedKey = Integer.toString(runners[i]) + "." + Integer.toString(i);
ranking.put(sortedKey, i);
}
// Print the results
int pos = 1;
for ( Map.Entry entry : ranking.entrySet() )
{
String key = entry.getKey();
String distance = key.subString(0, key.indexOf(".")); // chop off the "." + runners number.
System.out.println("#" + pos + // position
"." + entry.getValue() + // who
", Distance = " + distance); // distance covered
pos++; // this does take in account whether multiple runners finished on the same distance.
}
}
}
I want to put State objects (which are HashMaps with Character as key and State as Value into an ArrayList named allStates. Should I override the equals and hashCode methods here? Why? How?
This code is for the Automaton and State classes I've built so far:
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);
}
}
}
}
If the automaton is a DFA, then one can use the Accessing String to ID the field.
An accessing String is any string that could be used to reach the state from the start state. One will have to build the string while building the DFA, however, it won't add more time complexity. (Yes, one then needs to hashcode/equal the string)
Or actually, ID the states by an increasing serial number/string should work for all automaton. Then hashcode/equal based on the ID.
Go for the 2nd one, easier and works better than 1, unless you want to take care of the duplicated states.
Yes, you need the hashcode and equals for a user defined type to work with hash.