/*
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 * 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;
    }
}

import java.util.*;

public class RecycledNumbers {
    private final int A;
    private final int B;
    private final boolean[] allNumbers;

    public RecycledNumbers(int A, int B) {
        this.A = A;
        this.B = B;
        //numbers are A + i, where i is the array index
        allNumbers = new boolean[B - A + 1];
    }

    public int getDistinctPairsCount() {
        int distinctPairs = 0;
        for (int i = 0; i < allNumbers.length; i++) {
            if (!allNumbers[i]) {
                int number = indexToNumber(i);
                Set<String> recyclings = (number > 9) ? getRecyclings(number) : Collections.<String>emptySet();
                if (!recyclings.isEmpty()) ignore(recyclings);
                int numberOfDistinctPairs = recyclings.isEmpty() ? 0 : getNumberOfDistinctPairs(recyclings);
                distinctPairs += numberOfDistinctPairs;
            }
        }
        return distinctPairs;
    }

    private int getNumberOfDistinctPairs(Set<String> recyclings) {
        int recyclingsThatCount = 0;
        for (String s : recyclings) {
            int number = Integer.parseInt(s);
            if (withinBounds(number) && doesntStartWithZero(s))
                recyclingsThatCount++;
        }

        int pairs = recyclingsThatCount * (recyclingsThatCount - 1) / 2;
        return pairs;
    }

    private boolean doesntStartWithZero(String s) {
        boolean result = s.charAt(0) != '0';
        return result;
    }

    private boolean withinBounds(int number) {
        boolean result = number >= A && number <= B;
        return result;
    }

    private void ignore(Set<String> recyclings) {
        //set them to true in the array
        for (String s : recyclings) {
            int number = Integer.parseInt(s);
            if (withinBounds(number))
                allNumbers[numberToIndex(number)] = true;
        }
    }

    private int numberToIndex(int number) {
        return number - A;
    }

    private int indexToNumber(int i) {
        return i + A;
    }

    private Set<String> getRecyclings(int number) {
        String numberAsString = Integer.toString(number);
        int totalDigits = numberAsString.length();
        Set recyclings = new HashSet<String>();
        for (int i = totalDigits - 1; i >= 0; i--) {
            recyclings.add(numberAsString.substring(i, totalDigits) + numberAsString.substring(0, i));
        }
        return recyclings;
    }


}
