/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package recyclednumbers;

import java.util.HashSet;

/**
 *
 * @author vandit
 */
public class RecycleNumbers {

    private HashSet<String> numbers = new HashSet<String>();
    private HashSet<String> initialTempNumbers = new HashSet<String>();
    private HashSet<String> finalTempNumbers = new HashSet<String>();

    HashSet<Pair> numberPairs = new HashSet<Pair>();


    private void findRecycledNumbers(int start, int end, int places) {


        for (int i = start; i <= end; i++) {
            String initialNumber = Integer.toString(i);
            //if (!(numbers.contains(initialNumber) || finalTempNumbers.contains(initialNumber))) {

                StringBuffer tempNumber = new StringBuffer(initialNumber);
                int len = tempNumber.length();
                int startIndexToMove = len - places;
                String tempString = tempNumber.substring(startIndexToMove);
                if ((places == 1 && tempString.equals("0")) || tempString.charAt(0) == '0') {
                    continue;
                }
                tempNumber.delete(startIndexToMove, len);
                String finalTempNumber = tempString + tempNumber.toString();

                if (! (finalTempNumber.equals(initialNumber) || Integer.parseInt(finalTempNumber) > end || Integer.parseInt(finalTempNumber) < Integer.parseInt(initialNumber))) {
                    numbers.add(initialNumber);
                    finalTempNumbers.add(finalTempNumber);
                    Pair pair = new Pair(finalTempNumber,initialNumber);
                    numberPairs.add(pair);
                }
            }

        

    }

    public HashSet<Pair> findAllRecycledNumbers(int start, int end) {
        int length = Integer.toString(start).length();
        for (int i = 1; i < length; i++) {
            findRecycledNumbers(start, end, i);
        }
        return numberPairs;
    }
}

package fixjava;

import java.util.ArrayList;
import java.util.HashMap;

/**
 * Get the index of the given key if this key has been assigned an index before, and if not, allocate a new index for it by
 * incrementing a counter that starts at zero, and return the new index.
 */
public class UniqueIndexAllocator<T> {

	private HashMap<T, Integer> map = new HashMap<T, Integer>();
	private ArrayList<T> orderedKeys = new ArrayList<T>();

	public UniqueIndexAllocator() {
	}

	/** Allocate unique indices for each item in the given collection. Read back the indices using the other methods. */
	public UniqueIndexAllocator(Iterable<T> collection) {
		for (T it : collection)
			getOrAllocateIndex(it);
	}

	/** Get the assigned index for a key, or assign it a new unique index if this key has not previously been assigned an index */
	public int getOrAllocateIndex(T key) {
		Integer currIdx = map.get(key);
		if (currIdx == null) {
			map.put(key, currIdx = orderedKeys.size());
			orderedKeys.add(key);
		}
		return currIdx;
	}

	/** Get all the keys as a list in their index order */
	public ArrayList<T> getOrderedKeys() {
		return orderedKeys;
	}

	/** Get all the keys as an array in their index order */
	@SuppressWarnings("unchecked")
	public T[] getOrderedKeysAsArray() {
		return (T[]) orderedKeys.toArray();
	}

	/** Get the mapping from key to index */
	public HashMap<T, Integer> getKeyToIndexMap() {
		return map;
	}

	/** Return the number of allocated indices, i.e. the number of unique keys */
	public int numIndices() {
		return orderedKeys.size();
	}
}
