/*
 * 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 jp.funnything.competition.util;

import java.util.Arrays;
import java.util.Iterator;

/**
 * Do NOT change the element in iteration
 */
public class Permutation implements Iterable< int[] > , Iterator< int[] > {
    public static int[] fromNumber( long value , final int n ) {
        final int[] data = new int[ n ];

        for ( int index = 0 ; index < n ; index++ ) {
            data[ index ] = index;
        }

        for ( int index = 1 ; index < n ; index++ ) {
            final int pos = ( int ) ( value % ( index + 1 ) );

            value /= index + 1;

            final int swap = data[ index ];
            data[ index ] = data[ pos ];
            data[ pos ] = swap;
        }

        return data;
    }

    public static long toNumber( final int[] perm ) {
        final int[] data = Arrays.copyOf( perm , perm.length );

        long c = 0;

        for ( int index = data.length - 1 ; index > 0 ; index-- ) {
            int pos = 0;
            for ( int index_ = 1 ; index_ <= index ; index_++ ) {
                if ( data[ index_ ] > data[ pos ] ) {
                    pos = index_;
                }
            }

            final int t = data[ index ];
            data[ index ] = data[ pos ];
            data[ pos ] = t;

            c = c * ( index + 1 ) + pos;
        }

        return c;
    }

    private final int _n;
    private final int[] _data;
    private final int[] _count;
    int _k;

    public Permutation( final int n ) {
        _n = n;

        _data = new int[ n ];
        for ( int index = 0 ; index < n ; index++ ) {
            _data[ index ] = index;
        }

        _count = new int[ n + 1 ];
        for ( int index = 1 ; index <= n ; index++ ) {
            _count[ index ] = index;
        }

        _k = 1;
    }

    @Override
    public boolean hasNext() {
        return _k < _n;
    }

    @Override
    public Iterator< int[] > iterator() {
        return this;
    }

    @Override
    public int[] next() {
        final int i = _k % 2 != 0 ? _count[ _k ] : 0;

        final int t = _data[ _k ];
        _data[ _k ] = _data[ i ];
        _data[ i ] = t;

        for ( _k = 1 ; _count[ _k ] == 0 ; _k++ ) {
            _count[ _k ] = _k;
        }
        _count[ _k ]--;

        return _data;
    }

    @Override
    public void remove() {
    }
}
