Vector inside a Vector

Question

Help me, friends.
A vector "V" contains elements which are also vectors, say "v". E.g.:
V = {{1,2,3},{1,3,4,5},{2,4,5},{5,6,7}}
How to implement: if the first element of vector "v" are the same, combines the two vectors "v" AND if the two vectors "v" contains the same element for the rest (2nd, 3rd, etc), remove duplicate.
So the output for above example will be:
V = {{1,2,3,4,5},{2,4,5},{5,6,7}}
Thanks you for your help.

Answer 1

Thanks.
Another problem. I've tried to find the all pairs.
<code>
import java.io.*;
import java.util.*;
public class SequenceFacade {
     private HashMap map;
     public SequenceFacade() {
          map = new HashMap();     
     } // end default constructor
     /**     Task: Find all the pairs with input gap.
     *     @param inputFile a text file to be read
     *     @param gap no. of words between the pair
     public HashMap findPairs(String inputFile, String outputFile, int gap) throws Exception {
          File textFile = new File(inputFile);
          FileReader reader = new FileReader(textFile);
          BufferedReader br = new BufferedReader(reader);          
          FileWriter writer = new FileWriter(outputFile);
          PrintWriter pw = new PrintWriter(writer);
          String line = br.readLine();
          Vector words = new Vector();
          Object value;
          Vector indexList;
          int docIndex = 0;
          int totalPairs = 0;
          while(line != null) {
               StringTokenizer st = new StringTokenizer(line);
               while(st.hasMoreTokens())
                    words.addElement(st.nextToken());
               int noOfWords = words.size();
               for(int i = 0; i < noOfWords; i++) {
                    int j = i + (gap+1);
                    if(i < (noOfWords - (gap+1))) {
                         for(int k = i+1; k <= j; k++) {
                              Vector sequence = new Vector();
                              sequence.addElement(words.elementAt(i));
                              sequence.addElement(words.elementAt(k));
                              Vector index = new Vector();
                              index.addElement(new Integer(docIndex));
                              index.addElement(new Integer(i));
                              index.addElement(new Integer(k));
                              value = map.get(sequence);
                              if(value == null) {
                                   indexList = new Vector();
                                   map.put(sequence, indexList);
                              else {
                                   indexList = (Vector)value;
                              totalPairs++;
                              indexList.addElement(index);
                    else {
                         for(int k = i+1; k < noOfWords; k++) {
                              Vector sequence = new Vector();
                              sequence.addElement(words.elementAt(i));
                              sequence.addElement(words.elementAt(k));
                              Vector index = new Vector();
                              index.addElement(new Integer(docIndex));
                              index.addElement(new Integer(i));
                              index.addElement(new Integer(k));
                              value = map.get(sequence);
                              if(value == null) {
                                   indexList = new Vector();
                                   map.put(sequence, indexList);
                              else {
                                   indexList = (Vector)value;
                              totalPairs++;
                              indexList.addElement(index);
               } // end for
               docIndex++;
               line = br.readLine();
               words = new Vector();
          } // end while
          System.out.println("Total no. of pairs : "+map.size());
          System.out.println("Total no. of all pairs : "+totalPairs);
          Set set = map.entrySet();
          List setList = new ArrayList(set);
          //Collections.sort(setList, new MyCompare());
          for(Iterator it = setList.iterator(); it.hasNext();)
               pw.println(it.next());
          br.close();
          pw.close();
          return map;
     } // end findPairs()
} // end class SequenceFacade
</code>
The problem is when the key has a value which is a Vector that contains vector v. if the first element of vectors v are the same, then just append the vector.
Eg.
"hello world" which is found in line 1, "hello" in position 2, "world" in position 3.
So:
[hello, world]=[[1,2,3]]
if the words "hello word" also found in the same line but different position for each words, we just append the vector. Say, another "hello world" also found in line 1, "hello" in position 6, world in position 8.
We just append it like this:
[hello, world]=[[1,2,3,6,8]]
Anyone can help me edit the above algorithm? Thanks.