import java.util.ArrayList;

import java.util.List;

public class SequentialDigits {

public static void main(String[] args) {

System.out.println(sequentialDigits(100, 300));

}

public static List<Integer> sequentialDigits(int low, int high) {

String lowValue = String.valueOf(low);

String highValue = String.valueOf(high);

int lowLen = lowValue.length();

int upperLen = highValue.length();

String sample = "123456789";

List<Integer> result = new ArrayList<>();

for(int length = lowLen; length <= upperLen; length++)

{

int i = 0;

StringBuilder str = new StringBuilder();

for(int j = 0; j < sample.length(); j++)

{

str.append(sample.charAt(j));

if(j - i + 1 > length)

{

str.deleteCharAt(0);

i++;

}

if(j - i + 1 == length)

{

int value = Integer.parseInt(str.toString());

if(value >= low && value <= high)

{

result.add(value);

}

}

}

}

return result;

}

}