Develop Reference

StringBuilder Duplicates the last character in the delete

I do not know the site, and I have only asked one question here. I have no idea - how to handle a code problem. I tried a lot - but I could not fix.
I use StringBuilder - for because of its benefits according to the standard string
I want to delete the first character in the string - but the character that appears in the last place - is duplicated - in the last two places.
for example:
i have the String abcdef, when i delete - the first instace - 'a':
i got back the String bcdeff
well i try - to set the length of the String to original length minus one - but this dont give any result.
i try also - to set the string to new String - and after that - send the String that i was save in tmp string - but this do help either.
public void appendBuffer(StringBuilder dictionary)
{
for (int i = 0; i < appendToWindowBuffer; i++) {
if(dictionary.length() == windowSize)
{
dictionary.deleteCharAt(0);
}
if(nextByteIndex<source.length )
{
dictionary.append((char)source[nextByteIndex]);
nextByteIndex++;
}
else
{
currentLookaheadBufferSize--;
}
if(currentSearchBufferSize < searchBufferSize)
{
currentSearchBufferSize++;
}
}
appendToWindowBuffer = 0;
}
full code:
main class
import java.io.IOException;
public class Main {
public static void main(String[] args) throws IOException
{
System.out.println("main");
String inPath = "C:\\Users\\avraam\\Documents\\final-assignment\\LZ77\\source.txt";
String outPath = "C:\\Users\\avraam\\Documents\\final-assignment\\LZ77\\encoded.txt";
String decompressedPath = "C:\\Users\\avraam\\Documents\\final-assignment\\LZ77\\decoded.txt";
int windowSize = 14;
int lookaheadBufferSize = 6;
LZ77 compress = new LZ77(inPath,outPath,windowSize,lookaheadBufferSize);
compress.compress();
}
}
match class
public class Match {
protected int length;
protected int offset;
protected String value;
public Match(int length, int offset, String value)
{
this.length=length;
this.offset=offset;
this.value = value;
}
public void SetOffset(int offset) { this.offset = offset; }
public void SetLength(int length) { this.length = length; }
public void SetValue(String value) { this.value = value; }
public void AddValue(char value) { this.value += value; }
public void Reset()
{
this.offset = 0;
this.length = 0;
this.value = "";
}
}
LZ77 class
import java.io.File;
import java.io.IOException;
import java.nio.file.Files;
import java.util.Arrays;
public class LZ77 {
private String inPath = null;
private String outPath = null;
private File inFile;
private File outFile;
private final int windowSize;
private final int lookaheadBufferSize;
private final int searchBufferSize;
private int nextByteIndex = 0;
//private int lookAheadIndex = 0; //not always should be (windowsize - lookaheadBufferSize.) in the end maybr will be less character in the lookAhead buffer. the index when LookAhead start is equel to the length of SearchBuffer
private int currentSearchBufferSize = 0;
private int currentLookaheadBufferSize = 0;
private int appendToWindowBuffer = 0;
private byte[] source = null;
public LZ77(String inPath,String outPath,int windowSize,int lookaheadBufferSize) throws IOException
{
this.inPath = inPath;
this.outPath = outPath;
this.inFile = new File(inPath);
this.outFile = new File(outPath);
this.windowSize = windowSize;
this.lookaheadBufferSize = lookaheadBufferSize;
this.searchBufferSize = windowSize - lookaheadBufferSize;
this.source = Files.readAllBytes(inFile.toPath());
}
public void compress() throws IOException
{
/*
* 1. create whole windowBuffer (named - `dictionary`)- that will by used by lookahead and by search Buffers.
* 2. create compressed data - where the data that compressed will be send.
* 3. initialize dictionary - look a head buffer by giving it the size of `lookaheadBuffer`.
* 4. start encode.
* 5. make the encode.
*/
System.out.println("compress");
System.out.println("read the file.");
System.out.println("check if source array work: ");
for (int element: source) {
System.out.print((char)element + "");
}
System.out.println("call to bufferInitialize function");
StringBuilder dictionary = new StringBuilder();
bufferInitialize(dictionary);
System.out.println(dictionary.toString());
StringBuilder compressed = new StringBuilder();
encode(dictionary,compressed);
}
public void bufferInitialize(StringBuilder dictionary)
{
System.out.println("bufferInitialize");
for (int i = 0; i < lookaheadBufferSize; i++) {
dictionary.append((char)source[nextByteIndex]);
nextByteIndex++;
currentLookaheadBufferSize++;
}
// initialize the buffer in the beginning with look a head buffer.
}
public void bufferUpdate()
{
// gets int length - and read those number of bytes - from `inPath` source file.
}
public void encode(StringBuilder dictionary,StringBuilder compressed)
{
//while(nextByteIndex < source.length)
while(currentLookaheadBufferSize > 0)
{
Match match = findMatch(dictionary);
System.out.print("<"+match.offset + ","+match.length+","+ dictionary.charAt(currentSearchBufferSize + match.length) + ">");
appendToWindowBuffer = increaseBuffer(match.length);
appendBuffer(dictionary);
}
/**
* do while you reach to the end of the file
* check if there any possible match
* if do so
* find the maxMatch try always to add another character DONE
* call update function -
* the function will update the
* windowbuffer(dictionary), DONE
* nextByteIndex and DONE
* the position of the index that begins the lookAheadBuffer
* and size of the lookahead and
* search buffers, and
* reset the appendToWindowBuffer. DONE
*/
}
public void convertStringToBits()
{
}
public Match findMatch(StringBuilder dictionary)
{
/**
* function get the window buffer - and index to start.
* the function will be find the max match that starts from index 0 to index start (we cant start search after the `start index`)
* because this parts belong to the look a head buffer.
* #param
* #return
*/
Match match= new Match(0,0, "");
String matchedString = null;
int offset;
int matchLookAheadIndex = currentSearchBufferSize;
if(!haveAnyMatch(dictionary))
{
addMatch();
}
else {
matchedString = "" + dictionary.charAt(matchLookAheadIndex);
offset = findMatchIndex(dictionary,matchedString);
while(offset != -1)
{
match.SetLength(match.length + 1);
match.SetOffset(offset);
match.SetValue(matchedString);
matchLookAheadIndex++;
matchedString +=dictionary.charAt(matchLookAheadIndex);
offset = findMatchIndex(dictionary,matchedString);
}
}
return match;
}
public int findMatchIndex(StringBuilder dictionary,String value)
{
int stringLength = value.length();
String tmpMatch = null;
int offsetMatch;
for (int i = currentSearchBufferSize - 1; i >=0; i--)
{
tmpMatch = dictionary.substring(i, i +stringLength );
offsetMatch = currentSearchBufferSize - i;
if(tmpMatch.equals(value))
{
System.out.println("data was match is searchWindow");
System.out.println("the offset from LookAHead is: " + offsetMatch);
return offsetMatch;
}
}
return -1;
}
public boolean haveAnyMatch(StringBuilder dictionary)
{
if (currentSearchBufferSize == 0)
{
System.out.println("dont have match - search buffer is empty now");
return false;
}
if(!isExistInSearchBuffer(dictionary,dictionary.charAt(currentSearchBufferSize)))
{
System.out.println("dont have match - the first character in lookAheadBuffer wasn't found in searchBuffer");
return false;
}
return true;
/*
* check:
* if search buffer is empty
* if the needed character isn't exist in the search buffer
* if the current value is big enough - and match was not found.
*/
}
public boolean isExistInSearchBuffer(StringBuilder dictionary, char isCharAtDictionary)
{
for (int i = 0; i < currentSearchBufferSize; i++) {
if(dictionary.charAt(i) == isCharAtDictionary)
{
return true;
}
}
return false;
}
public void nextMatch(StringBuilder dictionary)
{
/**
* #param: value, window buffer.
* #description: find the current match with the needed value in the search buffer boundaries.
*/
}
public int increaseBuffer(int matchLength)
{
return 1 + matchLength;
/*
* return int - that calulate by how many byte we need to increase the buffer
*/
}
public void addMatch()
{
}
public void addBitSize() {
}
public void appendBuffer(StringBuilder dictionary)
{
for (int i = 0; i < appendToWindowBuffer; i++) {
if(dictionary.length() == windowSize)
{
dictionary.deleteCharAt(0);
}
if(nextByteIndex<source.length )
{
dictionary.append((char)source[nextByteIndex]);
nextByteIndex++;
}
else
{
currentLookaheadBufferSize--;
}
if(currentSearchBufferSize < searchBufferSize)
{
currentSearchBufferSize++;
}
}
appendToWindowBuffer = 0;
}
}

This seems to work:
StringBuilder builder = new StringBuilder("abcdef");
builder.deleteCharAt(0);
System.out.println(builder.toString());
Prints: bcdef
How are you doing it?

the solution that work for me:
i need to write the decompress - to outout file.
I registered to the file - in CHAR - this is not true - need to register output in BYTE
WORNG WAY THAT I DO:
private void writeDecode (StringBuilder decompress) throws IOException
{
Writer write = new FileWriter(this.outFile);
write.write(decompress.toString());
write.close();
}
THE CORRECT WAY
private void WriteToFile(StringBuilder decodedData) throws IOException
{
FileOutputStream outputFileStream = new FileOutputStream(this.outPath);
for(int i = 0; i < decodedData.length(); i++)
{
byte currentByte = (byte)decodedData.charAt(i);
outputFileStream.write(currentByte);
}
outputFileStream.close();
}
I need to register in the file in BYTE - this is the right way.

Difficulty reading .txt data when running Stable Marriage algorithm in Java [closed]

Closed. This question needs debugging details. It is not currently accepting answers.
Edit the question to include desired behavior, a specific problem or error, and the shortest code necessary to reproduce the problem. This will help others answer the question.
Closed 2 years ago.
Improve this question
I am new to Java and I am trying to execute the code below regarding Stable Marrage algorithm, but when executing the code below you get the following error:
Error: For input string: "3 " Exception in thread "main"
java.lang.NullPointerException at
br.com.entrada.GaleShapley.(GaleShapley.java:21) at
br.com.entrada.GaleShapley.main(GaleShapley.java:166)
Gale Shapley Marriage Algorithm
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.InputStreamReader;
public class GaleShapley
{
private int N, engagedCount;
private String[][] menPref;
private String[][] womenPref;
private String[] men;
private String[] women;
private String[] womenPartner;
private boolean[] menEngaged;
/** Constructor **/
public GaleShapley(String[] m, String[] w, String[][] mp, String[][] wp)
{
N = mp.length;
engagedCount = 0;
men = m;
women = w;
menPref = mp;
womenPref = wp;
menEngaged = new boolean[N];
womenPartner = new String[N];
calcMatches();
}
/** function to calculate all matches **/
private void calcMatches()
{
while (engagedCount < N)
{
int free;
for (free = 0; free < N; free++)
if (!menEngaged[free])
break;
for (int i = 0; i < N && !menEngaged[free]; i++)
{
int index = womenIndexOf(menPref[free][i]);
if (womenPartner[index] == null)
{
womenPartner[index] = men[free];
menEngaged[free] = true;
engagedCount++;
}
else
{
String currentPartner = womenPartner[index];
if (morePreference(currentPartner, men[free], index))
{
womenPartner[index] = men[free];
menEngaged[free] = true;
menEngaged[menIndexOf(currentPartner)] = false;
}
}
}
}
printCouples();
}
/** function to check if women prefers new partner over old assigned partner **/
private boolean morePreference(String curPartner, String newPartner, int index)
{
for (int i = 0; i < N; i++)
{
if (womenPref[index][i].equals(newPartner))
return true;
if (womenPref[index][i].equals(curPartner))
return false;
}
return false;
}
/** get men index **/
private int menIndexOf(String str)
{
for (int i = 0; i < N; i++)
if (men[i].equals(str))
return i;
return -1;
}
/** get women index **/
private int womenIndexOf(String str)
{
for (int i = 0; i < N; i++)
if (women[i].equals(str))
return i;
return -1;
}
/** print couples **/
public void printCouples()
{
System.out.println("Couples are : ");
for (int i = 0; i < N; i++)
{
System.out.println(womenPartner[i] +" "+ women[i]);
}
}
/** main function **/
public static void main(String[] args)
{
System.out.println("Gale Shapley Marriage Algorithm\n");
/** list of men **/
String[] m = {"1", "2", "3"};
/** list of women **/
String[] w = {"1", "2", "3"};
/** men preference **/
String[][] mp = null ;
/** women preference **/
String[][] wp= null ;
// Input.txt is like
// 3 <--defines the size of array
// male preference array
// 1 3 2
// 1 2 3
// 2 3 1
//female preference array
//1 3 2
//2 1 3
//2 1 3
try{
FileInputStream fstream = new FileInputStream("input.txt");
DataInputStream in = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String strLine;
int line=0;
int k=0;
int n=0;
int i=0;
while ((strLine = br.readLine()) != null) {
if(line==0){
n =Integer.valueOf(strLine);
mp=new String[n][n];
wp=new String[n][n];
line++;
}
else{
String[] preferences=strLine.split(" ");
if(i<n){
mp[i]=preferences;
}
else{
wp[i-n]=preferences;
}
i++;
}
}
in.close();
}catch (Exception e){//Catch exception if any
System.err.println("Error: " + e.getMessage());
}
GaleShapley gs = new GaleShapley(m, w, mp, wp);
}
}
The program is not reading the input.txt input file completely. It is reading only the first line of this file. And I can't solve this. I think the problem should be in the code part below.
while ((strLine = br.readLine()) != null) {
if(line==0){
n =Integer.valueOf(strLine);
mp=new String[n][n];
wp=new String[n][n];
line++;
}
else{
String[] preferences=strLine.split(" ");
if(i<n){
mp[i]=preferences;
}
else{
wp[i-n]=preferences;
}
i++;
}
}
Below is the input file: input.txt
3
male preference array
1 3 2
1 2 3
2 3 1
female preference array
1 3 2
2 1 3
2 1 3

The error is thrown due this : 3 => it contains a whitespace
And when you call the Integer.parse(N), N cannot be parsed to Integer while there's this whitespaces,
To resolve this, i used strLine.trim();
women[i].equals(str) : you are comparing here a string to an Integer is always false and the result of your function womenIndexOf is -1, and this is going to throw an exception of IndexOutOfBounds Exception when using the -1 as index
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.InputStreamReader;
public class GaleShapley {
private int N, engagedCount;
private String[][] menPref;
private String[][] womenPref;
private String[] men;
private String[] women;
private String[] womenPartner;
private boolean[] menEngaged;
/** Constructor **/
public GaleShapley() {
}
public GaleShapley(String[] m, String[] w, String[][] mp, String[][] wp) {
N = mp.length;
engagedCount = 0;
men = m;
women = w;
menPref = mp;
womenPref = wp;
menEngaged = new boolean[N];
womenPartner = new String[N];
calcMatches();
}
/** function to calculate all matches **/
private void calcMatches() {
while (engagedCount < N) {
int free;
for (free = 0; free < N; free++)
if (!menEngaged[free])
break;
for (int i = 0; i < N && !menEngaged[free]; i++) {
int index = womenIndexOf(menPref[free][i]);
if (womenPartner[index] == null) {
womenPartner[index] = men[free];
menEngaged[free] = true;
engagedCount++;
} else {
String currentPartner = womenPartner[index];
if (morePreference(currentPartner, men[free], index)) {
womenPartner[index] = men[free];
menEngaged[free] = true;
menEngaged[menIndexOf(currentPartner)] = false;
}
engagedCount++;
}
}
}
printCouples();
}
/** function to check if women prefers new partner over old assigned partner **/
private boolean morePreference(String curPartner, String newPartner, int index) {
for (int i = 0; i < N; i++) {
if (womenPref[index][i].equals(newPartner))
return true;
if (womenPref[index][i].equals(curPartner))
return false;
}
return false;
}
/** get men index **/
private int menIndexOf(String str) {
for (int i = 0; i < N; i++)
if (men[i].equals(str))
return i;
return -1;
}
/** get women index **/
private int womenIndexOf(String str) {
for (int i = 0; i < N; i++) {
if (women[i].equals(str))
return i;
}
return -1;
}
/** print couples **/
public void printCouples() {
System.out.println("Couples are : ");
for (int i = 0; i < N; i++) {
System.out.println(womenPartner[i] + " " + women[i]);
}
}
/** main function **/
public static void main(String[] args) {
System.out.println("Gale Shapley Marriage Algorithm\n");
/** list of men **/
String[] m = { "1", "2", "3" };
/** list of women **/
String[] w = { "1", "2", "3" };
/** men preference **/
String[][] mp = null;
/** women preference **/
String[][] wp = null;
try {
FileInputStream fstream = new FileInputStream("C:\\Users\\Youssef\\Projects\\STS\\TEST\\src\\input");
DataInputStream in = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String strLine;
int line = 0;
int n = 0;
int i = 0;
while ((strLine = br.readLine()) != null) {
if (line == 0) {
n = Integer.valueOf(strLine.trim());
mp = new String[n][n];
wp = new String[n][n];
line++;
} else {
if (strLine != null && !strLine.equals("") && !strLine.contains("male")
&& !strLine.contains("female")) {
String[] preferences = strLine.split(" ");
if (i < n) {
mp[i] = preferences;
} else {
if (i - n < w.length) {
wp[i - n] = preferences;
}
}
i++;
}
}
}
in.close();
new GaleShapley(m, w, mp, wp);
} catch (Exception e) {// Catch exception if any
e.printStackTrace();
System.err.println("Error: " + e.getMessage());
}
}
}

Follows the code running below:
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.io.InputStreamReader;
public class GaleShapley
{
private int N, engagedCount;
private String[][] menPref;
private String[][] womenPref;
private String[] men;
private String[] women;
private String[] womenPartner;
private boolean[] menEngaged;
public GaleShapley() {}
/** Constructor **/
public GaleShapley(String[] m, String[] w, String[][] mp, String[][] wp)
{
N = mp.length;
engagedCount = 0;
men = m;
women = w;
menPref = mp;
womenPref = wp;
menEngaged = new boolean[N];
womenPartner = new String[N];
calcMatches();
}
/** function to calculate all matches **/
private void calcMatches()
{
while (engagedCount < N)
{
int free;
for (free = 0; free < N; free++)
if (!menEngaged[free])
break;
for (int i = 0; i < N && !menEngaged[free]; i++)
{
int index = womenIndexOf(menPref[free][i]);
if (womenPartner[index] == null)
{
womenPartner[index] = men[free];
menEngaged[free] = true;
engagedCount++;
}
else
{
String currentPartner = womenPartner[index];
if (morePreference(currentPartner, men[free], index))
{
womenPartner[index] = men[free];
menEngaged[free] = true;
menEngaged[menIndexOf(currentPartner)] = false;
}
}
}
}
printCouples();
}
/** function to check if women prefers new partner over old assigned partner **/
private boolean morePreference(String curPartner, String newPartner, int index)
{
for (int i = 0; i < N; i++)
{
if (womenPref[index][i].equals(newPartner))
return true;
if (womenPref[index][i].equals(curPartner))
return false;
}
return false;
}
/** get men index **/
private int menIndexOf(String str)
{
for (int i = 0; i < N; i++)
if (men[i].equals(str))
return i;
return -1;
}
/** get women index **/
private int womenIndexOf(String str)
{
for (int i = 0; i < N; i++)
if (women[i].equals(str))
return i;
return -1;
}
/** print couples **/
public void printCouples()
{
System.out.println("Couples are : ");
for (int i = 0; i < N; i++)
{
System.out.println(womenPartner[i] +" "+ women[i]);
}
}
/** main function **/
public static void main(String[] args) {
System.out.println("Gale Shapley Marriage Algorithm\n");
/** list of men **/
String[] m = { "1", "2", "3" };
/** list of women **/
String[] w = { "1", "2", "3" };
/** men preference **/
String[][] mp = null;
/** women preference **/
String[][] wp = null;
try {
FileInputStream fstream = new FileInputStream("src\\input.txt");
DataInputStream in = new DataInputStream(fstream);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
String strLine;
int line = 0;
int n = 0;
int i = 0;
while ((strLine = br.readLine()) != null) {
if (line == 0) {
n = Integer.valueOf(strLine.trim());
mp = new String[n][n];
wp = new String[n][n];
line++;
} else {
if (strLine != null && !strLine.equals("") && !strLine.contains("male")
&& !strLine.contains("female")) {
String[] preferences = strLine.split(" ");
if (i < n) {
mp[i] = preferences;
} else {
if (i - n < w.length) {
wp[i - n] = preferences;
}
}
i++;
}
}
}
in.close();
new GaleShapley(m, w, mp, wp);
} catch (Exception e) {// Catch exception if any
e.printStackTrace();
System.err.println("Error: " + e.getMessage());
}
}
}
The result is:
Gale Shapley Marriage Algorithm
Couples are :
1 1
2 2
3 3

Could not find or load main class in bash

I used jflex to generate a Java class and now I want to use it to get lexical analysis of a .txt file. The Java Class begins like this:
/* The following code was generated by JFlex 1.6.1 */
/**
* This class is a scanner generated by
* JFlex 1.6.1
* from the specification file <tt>patch.flex</tt>
*/
public class Patch {
/** This character denotes the end of file */
public static final int YYEOF = -1;
/** initial size of the lookahead buffer */
private static final int ZZ_BUFFERSIZE = 16384;
/** lexical states */
public static final int YYINITIAL = 0;
/**
* ZZ_LEXSTATE[l] is the state in the DFA for the lexical state l
* ZZ_LEXSTATE[l+1] is the state in the DFA for the lexical state l
* at the beginning of a line
* l is of the form l = 2*k, k a non negative integer
*/
private static final int ZZ_LEXSTATE[] = {
0, 0
};
/**
* Translates characters to character classes
*/
private static final String ZZ_CMAP_PACKED =
"\141\0\1\1\1\2\1\3\1\4\uffff\0\uffff\0\uffff\0\uffff\0\uffff\0\uffff\0\uffff\0\uffff\0\uffff\0\uffff\0\uffff\0\uffff\0\uffff\0\uffff\0\uffff\0\uffff\0\uffab\0";
/**
* Translates characters to character classes
*/
private static final char [] ZZ_CMAP = zzUnpackCMap(ZZ_CMAP_PACKED);
/**
* Translates DFA states to action switch labels.
*/
private static final int [] ZZ_ACTION = zzUnpackAction();
private static final String ZZ_ACTION_PACKED_0 =
"\1\0\2\1\3\0\1\2\2\0\2\2";
private static int [] zzUnpackAction() {
int [] result = new int[11];
int offset = 0;
offset = zzUnpackAction(ZZ_ACTION_PACKED_0, offset, result);
return result;
}
private static int zzUnpackAction(String packed, int offset, int [] result) {
int i = 0; /* index in packed string */
int j = offset; /* index in unpacked array */
int l = packed.length();
while (i < l) {
int count = packed.charAt(i++);
int value = packed.charAt(i++);
do result[j++] = value; while (--count > 0);
}
return j;
}
/**
* Translates a state to a row index in the transition table
*/
private static final int [] ZZ_ROWMAP = zzUnpackRowMap();
private static final String ZZ_ROWMAP_PACKED_0 =
"\0\0\0\5\0\12\0\12\0\17\0\24\0\31\0\36"+
"\0\31\0\5\0\36";
private static int [] zzUnpackRowMap() {
int [] result = new int[11];
int offset = 0;
offset = zzUnpackRowMap(ZZ_ROWMAP_PACKED_0, offset, result);
return result;
}
private static int zzUnpackRowMap(String packed, int offset, int [] result) {
int i = 0; /* index in packed string */
int j = offset; /* index in unpacked array */
int l = packed.length();
while (i < l) {
int high = packed.charAt(i++) << 16;
result[j++] = high | packed.charAt(i++);
}
return j;
}
/**
* The transition table of the DFA
*/
private static final int [] ZZ_TRANS = zzUnpackTrans();
private static final String ZZ_TRANS_PACKED_0 =
"\1\2\1\3\3\2\6\0\1\4\1\5\1\6\3\0"+
"\1\5\1\7\2\0\1\10\1\0\1\6\4\0\1\11"+
"\1\12\1\0\1\13\3\0";
private static int [] zzUnpackTrans() {
int [] result = new int[35];
int offset = 0;
offset = zzUnpackTrans(ZZ_TRANS_PACKED_0, offset, result);
return result;
}
private static int zzUnpackTrans(String packed, int offset, int [] result) {
int i = 0; /* index in packed string */
int j = offset; /* index in unpacked array */
int l = packed.length();
while (i < l) {
int count = packed.charAt(i++);
int value = packed.charAt(i++);
value--;
do result[j++] = value; while (--count > 0);
}
return j;
}
/* error codes */
private static final int ZZ_UNKNOWN_ERROR = 0;
private static final int ZZ_NO_MATCH = 1;
private static final int ZZ_PUSHBACK_2BIG = 2;
/* error messages for the codes above */
private static final String ZZ_ERROR_MSG[] = {
"Unknown internal scanner error",
"Error: could not match input",
"Error: pushback value was too large"
};
/**
* ZZ_ATTRIBUTE[aState] contains the attributes of state <code>aState</code>
*/
private static final int [] ZZ_ATTRIBUTE = zzUnpackAttribute();
private static final String ZZ_ATTRIBUTE_PACKED_0 =
"\1\0\1\11\1\1\3\0\1\1\2\0\1\11\1\1";
private static int [] zzUnpackAttribute() {
int [] result = new int[11];
int offset = 0;
offset = zzUnpackAttribute(ZZ_ATTRIBUTE_PACKED_0, offset, result);
return result;
}
private static int zzUnpackAttribute(String packed, int offset, int [] result) {
int i = 0; /* index in packed string */
int j = offset; /* index in unpacked array */
int l = packed.length();
while (i < l) {
int count = packed.charAt(i++);
int value = packed.charAt(i++);
do result[j++] = value; while (--count > 0);
}
return j;
}
/** the input device */
private java.io.Reader zzReader;
/** the current state of the DFA */
private int zzState;
/** the current lexical state */
private int zzLexicalState = YYINITIAL;
/** this buffer contains the current text to be matched and is
the source of the yytext() string */
private char zzBuffer[] = new char[ZZ_BUFFERSIZE];
/** the textposition at the last accepting state */
private int zzMarkedPos;
/** the current text position in the buffer */
private int zzCurrentPos;
/** startRead marks the beginning of the yytext() string in the buffer */
private int zzStartRead;
/** endRead marks the last character in the buffer, that has been read
from input */
private int zzEndRead;
/** number of newlines encountered up to the start of the matched text */
private int yyline;
/** the number of characters up to the start of the matched text */
private int yychar;
/**
* the number of characters from the last newline up to the start of the
* matched text
*/
private int yycolumn;
/**
* zzAtBOL == true <=> the scanner is currently at the beginning of a line
*/
private boolean zzAtBOL = true;
/** zzAtEOF == true <=> the scanner is at the EOF */
private boolean zzAtEOF;
/** denotes if the user-EOF-code has already been executed */
private boolean zzEOFDone;
/**
* The number of occupied positions in zzBuffer beyond zzEndRead.
* When a lead/high surrogate has been read from the input stream
* into the final zzBuffer position, this will have a value of 1;
* otherwise, it will have a value of 0.
*/
private int zzFinalHighSurrogate = 0;
/**
* Creates a new scanner
*
* #param in the java.io.Reader to read input from.
*/
public Patch(java.io.Reader in) {
this.zzReader = in;
}
/**
* Unpacks the compressed character translation table.
*
* #param packed the packed character translation table
* #return the unpacked character translation table
*/
private static char [] zzUnpackCMap(String packed) {
char [] map = new char[0x110000];
int i = 0; /* index in packed string */
int j = 0; /* index in unpacked array */
while (i < 44) {
int count = packed.charAt(i++);
char value = packed.charAt(i++);
do map[j++] = value; while (--count > 0);
}
return map;
}
/**
* Refills the input buffer.
*
* #return <code>false</code>, iff there was new input.
*
* #exception java.io.IOException if any I/O-Error occurs
*/
private boolean zzRefill() throws java.io.IOException {
/* first: make room (if you can) */
if (zzStartRead > 0) {
zzEndRead += zzFinalHighSurrogate;
zzFinalHighSurrogate = 0;
System.arraycopy(zzBuffer, zzStartRead,
zzBuffer, 0,
zzEndRead-zzStartRead);
/* translate stored positions */
zzEndRead-= zzStartRead;
zzCurrentPos-= zzStartRead;
zzMarkedPos-= zzStartRead;
zzStartRead = 0;
}
/* is the buffer big enough? */
if (zzCurrentPos >= zzBuffer.length - zzFinalHighSurrogate) {
/* if not: blow it up */
char newBuffer[] = new char[zzBuffer.length*2];
System.arraycopy(zzBuffer, 0, newBuffer, 0, zzBuffer.length);
zzBuffer = newBuffer;
zzEndRead += zzFinalHighSurrogate;
zzFinalHighSurrogate = 0;
}
/* fill the buffer with new input */
int requested = zzBuffer.length - zzEndRead;
int numRead = zzReader.read(zzBuffer, zzEndRead, requested);
/* not supposed to occur according to specification of java.io.Reader */
if (numRead == 0) {
throw new java.io.IOException("Reader returned 0 characters. See JFlex examples for workaround.");
}
if (numRead > 0) {
zzEndRead += numRead;
/* If numRead == requested, we might have requested to few chars to
encode a full Unicode character. We assume that a Reader would
otherwise never return half characters. */
if (numRead == requested) {
if (Character.isHighSurrogate(zzBuffer[zzEndRead - 1])) {
--zzEndRead;
zzFinalHighSurrogate = 1;
}
}
/* potentially more input available */
return false;
}
/* numRead < 0 ==> end of stream */
return true;
}
/**
* Closes the input stream.
*/
public final void yyclose() throws java.io.IOException {
zzAtEOF = true; /* indicate end of file */
zzEndRead = zzStartRead; /* invalidate buffer */
if (zzReader != null)
zzReader.close();
}
/**
* Resets the scanner to read from a new input stream.
* Does not close the old reader.
*
* All internal variables are reset, the old input stream
* <b>cannot</b> be reused (internal buffer is discarded and lost).
* Lexical state is set to <tt>ZZ_INITIAL</tt>.
*
* Internal scan buffer is resized down to its initial length, if it has grown.
*
* #param reader the new input stream
*/
public final void yyreset(java.io.Reader reader) {
zzReader = reader;
zzAtBOL = true;
zzAtEOF = false;
zzEOFDone = false;
zzEndRead = zzStartRead = 0;
zzCurrentPos = zzMarkedPos = 0;
zzFinalHighSurrogate = 0;
yyline = yychar = yycolumn = 0;
zzLexicalState = YYINITIAL;
if (zzBuffer.length > ZZ_BUFFERSIZE)
zzBuffer = new char[ZZ_BUFFERSIZE];
}
/**
* Returns the current lexical state.
*/
public final int yystate() {
return zzLexicalState;
}
/**
* Enters a new lexical state
*
* #param newState the new lexical state
*/
public final void yybegin(int newState) {
zzLexicalState = newState;
}
/**
* Returns the text matched by the current regular expression.
*/
public final String yytext() {
return new String( zzBuffer, zzStartRead, zzMarkedPos-zzStartRead );
}
/**
* Returns the character at position <tt>pos</tt> from the
* matched text.
*
* It is equivalent to yytext().charAt(pos), but faster
*
* #param pos the position of the character to fetch.
* A value from 0 to yylength()-1.
*
* #return the character at position pos
*/
public final char yycharat(int pos) {
return zzBuffer[zzStartRead+pos];
}
/**
* Returns the length of the matched text region.
*/
public final int yylength() {
return zzMarkedPos-zzStartRead;
}
/**
* Reports an error that occured while scanning.
*
* In a wellformed scanner (no or only correct usage of
* yypushback(int) and a match-all fallback rule) this method
* will only be called with things that "Can't Possibly Happen".
* If this method is called, something is seriously wrong
* (e.g. a JFlex bug producing a faulty scanner etc.).
*
* Usual syntax/scanner level error handling should be done
* in error fallback rules.
*
* #param errorCode the code of the errormessage to display
*/
private void zzScanError(int errorCode) {
String message;
try {
message = ZZ_ERROR_MSG[errorCode];
}
catch (ArrayIndexOutOfBoundsException e) {
message = ZZ_ERROR_MSG[ZZ_UNKNOWN_ERROR];
}
throw new Error(message);
}
/**
* Pushes the specified amount of characters back into the input stream.
*
* They will be read again by then next call of the scanning method
*
* #param number the number of characters to be read again.
* This number must not be greater than yylength()!
*/
public void yypushback(int number) {
if ( number > yylength() )
zzScanError(ZZ_PUSHBACK_2BIG);
zzMarkedPos -= number;
}
/**
* Resumes scanning until the next regular expression is matched,
* the end of input is encountered or an I/O-Error occurs.
*
* #return the next token
* #exception java.io.IOException if any I/O-Error occurs
*/
public int yylex() throws java.io.IOException {
int zzInput;
int zzAction;
// cached fields:
int zzCurrentPosL;
int zzMarkedPosL;
int zzEndReadL = zzEndRead;
char [] zzBufferL = zzBuffer;
char [] zzCMapL = ZZ_CMAP;
int [] zzTransL = ZZ_TRANS;
int [] zzRowMapL = ZZ_ROWMAP;
int [] zzAttrL = ZZ_ATTRIBUTE;
while (true) {
zzMarkedPosL = zzMarkedPos;
boolean zzR = false;
int zzCh;
int zzCharCount;
for (zzCurrentPosL = zzStartRead ;
zzCurrentPosL < zzMarkedPosL ;
zzCurrentPosL += zzCharCount ) {
zzCh = Character.codePointAt(zzBufferL, zzCurrentPosL, zzMarkedPosL);
zzCharCount = Character.charCount(zzCh);
switch (zzCh) {
case '\u000B':
case '\u000C':
case '\u0085':
case '\u2028':
case '\u2029':
yyline++;
yycolumn = 0;
zzR = false;
break;
case '\r':
yyline++;
yycolumn = 0;
zzR = true;
break;
case '\n':
if (zzR)
zzR = false;
else {
yyline++;
yycolumn = 0;
}
break;
default:
zzR = false;
yycolumn += zzCharCount;
}
}
if (zzR) {
// peek one character ahead if it is \n (if we have counted one line too much)
boolean zzPeek;
if (zzMarkedPosL < zzEndReadL)
zzPeek = zzBufferL[zzMarkedPosL] == '\n';
else if (zzAtEOF)
zzPeek = false;
else {
boolean eof = zzRefill();
zzEndReadL = zzEndRead;
zzMarkedPosL = zzMarkedPos;
zzBufferL = zzBuffer;
if (eof)
zzPeek = false;
else
zzPeek = zzBufferL[zzMarkedPosL] == '\n';
}
if (zzPeek) yyline--;
}
zzAction = -1;
zzCurrentPosL = zzCurrentPos = zzStartRead = zzMarkedPosL;
zzState = ZZ_LEXSTATE[zzLexicalState];
// set up zzAction for empty match case:
int zzAttributes = zzAttrL[zzState];
if ( (zzAttributes & 1) == 1 ) {
zzAction = zzState;
}
zzForAction: {
while (true) {
if (zzCurrentPosL < zzEndReadL) {
zzInput = Character.codePointAt(zzBufferL, zzCurrentPosL, zzEndReadL);
zzCurrentPosL += Character.charCount(zzInput);
}
else if (zzAtEOF) {
zzInput = YYEOF;
break zzForAction;
}
else {
// store back cached positions
zzCurrentPos = zzCurrentPosL;
zzMarkedPos = zzMarkedPosL;
boolean eof = zzRefill();
// get translated positions and possibly new buffer
zzCurrentPosL = zzCurrentPos;
zzMarkedPosL = zzMarkedPos;
zzBufferL = zzBuffer;
zzEndReadL = zzEndRead;
if (eof) {
zzInput = YYEOF;
break zzForAction;
}
else {
zzInput = Character.codePointAt(zzBufferL, zzCurrentPosL, zzEndReadL);
zzCurrentPosL += Character.charCount(zzInput);
}
}
int zzNext = zzTransL[ zzRowMapL[zzState] + zzCMapL[zzInput] ];
if (zzNext == -1) break zzForAction;
zzState = zzNext;
zzAttributes = zzAttrL[zzState];
if ( (zzAttributes & 1) == 1 ) {
zzAction = zzState;
zzMarkedPosL = zzCurrentPosL;
if ( (zzAttributes & 8) == 8 ) break zzForAction;
}
}
}
// store back cached position
zzMarkedPos = zzMarkedPosL;
if (zzInput == YYEOF && zzStartRead == zzCurrentPos) {
zzAtEOF = true;
return YYEOF;
}
else {
switch (zzAction < 0 ? zzAction : ZZ_ACTION[zzAction]) {
case 1:
{ System.out.print(yytext());
}
case 3: break;
case 2:
{ System.out.println("***found match");
}
case 4: break;
default:
zzScanError(ZZ_NO_MATCH);
}
}
}
}
/**
* Runs the scanner on input files.
*
* This is a standalone scanner, it will print any unmatched
* text to System.out unchanged.
*
* #param argv the command line, contains the filenames to run
* the scanner on.
*/
public static void main(String argv[]) {
if (argv.length == 0) {
System.out.println("Usage : java Patch [ --encoding <name> ] <inputfile(s)>");
}
else {
int firstFilePos = 0;
String encodingName = "UTF-8";
if (argv[0].equals("--encoding")) {
firstFilePos = 2;
encodingName = argv[1];
try {
java.nio.charset.Charset.forName(encodingName); // Side-effect: is encodingName valid?
} catch (Exception e) {
System.out.println("Invalid encoding '" + encodingName + "'");
return;
}
}
for (int i = firstFilePos; i < argv.length; i++) {
Patch scanner = null;
try {
java.io.FileInputStream stream = new java.io.FileInputStream(argv[i]);
java.io.Reader reader = new java.io.InputStreamReader(stream, encodingName);
scanner = new Patch(reader);
while ( !scanner.zzAtEOF ) scanner.yylex();
}
catch (java.io.FileNotFoundException e) {
System.out.println("File not found : \""+argv[i]+"\"");
}
catch (java.io.IOException e) {
System.out.println("IO error scanning file \""+argv[i]+"\"");
System.out.println(e);
}
catch (Exception e) {
System.out.println("Unexpected exception:");
e.printStackTrace();
}
}
}
}
}
The shell keep giving me the error
Error: Could not find or load main class Patch
when I use the command like:
java Patch SearchText.txt
Besides, there's no error when I run:
javac Patch.java
I tried to set the path explicitly:
java -cp. Patch SearchText.txt
and got something like this:
{\rtf1\ansi\ansicpg1252\cocoartf1348\cocoasubrtf170
{\fonttbl\f0\fswiss\fcharset0 Helvetica;}
{\colortbl;\red255\green255\blue255;}
\margl1440\margr1440\vieww10800\viewh8400\viewkind0
\pard\tx720\tx1440\tx2160\tx2880\tx3600\tx4320\tx5040\tx5760\tx6480\tx7200\tx7920\tx8640\pardirnatural
\f0\fs24 \cf0 a+b+c+d}AmbertekiMacBook-Air:ADS4 amber95$ java Patch SearchText.txt
Error: Could not find or load main class Patch

Have you tried this?
java -cp ./ Patch file.txt

File I/O in Java

I have problems with the code for my own Vector class.
FIXED. Added reading and writing to file, but this try/catch things look too cumbersome for me. Maybe there's a better way of file I/O?
FIXED-2 Oh, I've just discovered "throws" and now my code looks really good. Thanks everyone for help! Here's the final version of Stack.java:
import java.util.Scanner;
import java.io.*;
class Vector {
private int[] vec;
private int length, pointer;
public Vector(int n) {
pointer = 0;
length = n;
vec = new int[length];
}
public int get(int i) {
return vec[i];
}
public void set(int i, int n) {
vec[i] = n;
}
public void push(int n) {
if (pointer == length) {
int[] nvec = new int[length*2];
for (int i = 0; i < length; i++)
nvec[i] = vec[i];
length *= 2;
vec = null;
vec = nvec;
}
vec[pointer++] = n;
}
public void delete() {
pointer--;
if (pointer == length / 4) {
int[] nvec = new int[length/2];
for (int i = 0; i <= pointer; i++)
nvec[i] = vec[i];
length /= 2;
vec = null;
vec = nvec;
}
}
public int size() {
return pointer;
}
public int actualSize() {
return length;
}
}
public class Stack {
public static void main(String[] args) throws IOException {
File ifile = new File("stack1.in");
BufferedReader reader = new BufferedReader(new FileReader(ifile));
File ofile = new File("stack1.out");
BufferedWriter writer = new BufferedWriter(new FileWriter(ofile));
int n = Integer.parseInt(reader.readLine());
Vector stack = new Vector(10);
for (int i = 0; i < n; i++) {
String s = reader.readLine();
if (s.charAt(0) == '-') {
writer.write(Integer.toString(stack.get(stack.size()-1)));
writer.write("\n");
stack.delete();
} else {
s = s.substring(2);
stack.push(Integer.parseInt(s));
}
}
writer.close();
reader.close();
}
}

Your syntax is wrong. Perhaps you meant something like this:
Vector stack = new Vector(10);
Also, are you sure you want your Vector class inside your Stack class? Also also, it's generally a bad idea to name your classes the same thing as existing Java classes.

Initialise the Vector class as below
Vector stack = new Vector(10);

Vector stack = new Vector(10);

How do I adapt this program to comply with the online judge?

I'm solving UVA's Edit Step Ladders on an uva sub-site named programming-challenges.com, but since I didn't get at all the format in which I'm supposed to test-input I simply took their sample input, put it into a text file and tested my code from there. Like this:
import java.io.*;
import java.util.*;
class Levenshtein {
private static int minimum(int a, int b, int c) {
if(a<=b && a<=c)
return a;
if(b<=a && b<=c)
return b;
return c;
}
public static int computeLevenshteinDistance(String str1, String str2) {
return computeLevenshteinDistance(str1.toCharArray(),
str2.toCharArray());
}
private static int computeLevenshteinDistance(char [] str1, char [] str2) {
int [][]distance = new int[str1.length+1][str2.length+1];
for(int i=0;i<=str1.length;i++)
distance[i][0]=i;
for(int j=0;j<=str2.length;j++)
distance[0][j]=j;
for(int i=1;i<=str1.length;i++)
for(int j=1;j<=str2.length;j++)
distance[i][j]= minimum(distance[i-1][j]+1,
distance[i][j-1]+1,
distance[i-1][j-1]+
((str1[i-1]==str2[j-1])?0:1));
return distance[str1.length][str2.length];
}
public static void main(String args[]){
ArrayList<String> theWords = new ArrayList<String>();
try {
String ruta="entradaLevenshtein.txt";
File myFile = new File (ruta);
FileReader fileReader = new FileReader(myFile);
BufferedReader reader = new BufferedReader(fileReader);
String line = null;
while ((line=reader.readLine())!=null){
System.out.println(line);
theWords.add(line);
}
reader.close();
}
catch (IOException ex){
ex.printStackTrace();
}
{}
// todo esto sólo para iniciar el arreglo
// ahora vienen las llamadas a Levenstein y las comparaciones
int maxEdit=0;
int actualEdit=0;
int wordsIndex1 =0, wordsIndex2=0;
while (wordsIndex1<= theWords.size())
{
while (wordsIndex2<= theWords.size()-1){
actualEdit=computeLevenshteinDistance(theWords.get(wordsIndex1),theWords.get(wordsIndex2));
if (actualEdit>maxEdit){maxEdit=actualEdit;}
wordsIndex2++;
}
wordsIndex1++;
}
System.out.println(maxEdit+1);
}
}
my input file being:
cat
dig
dog
fig
fin
fine
fog
log
wine
I'm supposed to make the code comply to the following pattern, thing is..I don't get where this thing is capturing its String:
import java.io.*;
import java.util.*;
class Modelo implements Runnable{
static String ReadLn(int maxLength){ // utility function to read from stdin,
// Provided by Programming-challenges, edit for style only
byte line[] = new byte [maxLength];
int length = 0;
int input = -1;
try{
while (length < maxLength){//Read untill maxlength
input = System.in.read();
if ((input < 0) || (input == '\n')) break; //or untill end of line ninput
line [length++] += input;
}
if ((input < 0) && (length == 0)) return null; // eof
return new String(line, 0, length);
}catch (IOException e){
return null;
}
}
public static void main(String args[]) // entry point from OS
{
Modelo myWork = new Modelo(); // Construct the bootloader
myWork.run(); // execute
}
public void run() {
new myStuff().run();
}
}
class myStuff implements Runnable{
public void run(){
try
{
/// PLACE YOUR JAVA CODE HERE
}catch(Exception e){
System.out.println("A Exception was generated");
}
}
// You can insert more classes here if you want.
}
Why should I place it where it says //place your code here and not here??
try{
while (length < maxLength){//Read untill maxlength
input = System.in.read();
if ((input < 0) || (input == '\n')) break; //or untill end of line input
line [length++] += input;
}
How do I manipulate the input??

I think the idea here is to write your program in the myStuff class, where it will be called in the run() method. From the run() method, you can use Modelo.ReadLn() to get your input.