Lukuvälit

import java.util.Scanner;
import java.util.ArrayList;
import java.util.List;
import java.lang.Math;

class lukuvalit {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        int n = Integer.parseInt(input.nextLine());

        List<String[]> numPairs = new ArrayList<String[]>();

        for (int i = 0; i < n; i++) {
            String numbers = input.nextLine();
            String[] nums = numbers.split(" ");
            numPairs.add(nums);
        }
        input.close();

        for (String[] ab : numPairs) {
            long a = Long.parseLong(ab[0]);
            long b = Long.parseLong(ab[1]);

            if (a == b) {
                if (isValid(Long.toString(a))) {
                    System.out.println(1);
                } else {
                    System.out.println(0);
                }
            } else {
                int output = 0;
                if (a == 0) {
                    a += 1;
                    output += 1;
                }
                long first = getStartIndex(a, b);
                long last = getEndIndex(a, b);

                if (first != -1L && last != -1L) {
                    int startBinaryVal = getBinary(Long.toString(first));
                    int endBinaryVal = getBinary(Long.toString(last));

                    int val = (endBinaryVal - startBinaryVal) + 1;
                    output += val;
                }

                System.out.println(output);
            }
        }

    }

    public static long getStartIndex(long a, long b) {
        if(isValid(Long.toString(a))){
            return a;
        }
        int exp = (int) Math.floor(Math.log10((double) a));
        long index = 0L;
        for (int i = exp; i >= 0; i--) {
            index += (long)Math.pow(10, i);
        }
        for (int i = 0; i <= exp; i++) {
            long substraction = (long) Math.pow(10, i);
            if (index - substraction >= a) {
                index = index - substraction;
            } else {
                break;
            }
        }
        if(index < a){
            index = (long)Math.pow(10, (exp+1));
        }
        if (index > b) {
            return -1L;
        }

        return index;
    }

    public static long getEndIndex(long a, long b) {
        if(isValid(Long.toString(b))){
            return b;
        }
        int exp = (int) Math.floor(Math.log10((double) b));
        long index = (long)Math.pow(10, exp);
        for (int i = 0; i < exp; i++) {
            long addition = (long) Math.pow(10, i);
            if (index + addition <= b) {
                index += addition;
            } else {
                break;
            }
        }
        if (index > b || index < a) {
            return -1L;
        }
        return index;
    }

   

    public static boolean isValid(String num) {
        boolean output = true;
        for (int i = 0; i < num.length(); i++) {
            char chr = num.charAt(i);
            if (chr != '1' && chr != '0') {
                output = false;
                break;
            }
        }
        return output;
    }

    public static int getBinary(String input) {
        int val = Integer.parseInt(input, 2);
        return val;

    }
}

Test 1

Group: 1, 2, 3

Verdict: ACCEPTED

Test 2

Group: 1, 2, 3

Verdict: ACCEPTED

Test 3

Group: 1, 2, 3

Verdict: ACCEPTED

Test 4

Group: 1, 2, 3

Verdict: ACCEPTED

Test 5

Group: 1, 2, 3

Verdict: ACCEPTED

Test 6

Group: 1, 2, 3

Verdict: ACCEPTED

Test 7

Group: 1, 2, 3

Verdict: ACCEPTED

Test 8

Group: 1, 2, 3

Verdict: ACCEPTED

Test 9

Group: 1, 2, 3

Verdict: ACCEPTED

Test 10

Group: 1, 2, 3

Verdict: ACCEPTED

Test 11

Group: 1, 2, 3

Verdict: ACCEPTED

Test 12

Group: 1, 2, 3

Verdict: ACCEPTED

Test 13

Group: 2, 3

Verdict: TIME LIMIT EXCEEDED

Test 14

Group: 2, 3

Verdict: TIME LIMIT EXCEEDED

Test 15

Group: 2, 3

Verdict: TIME LIMIT EXCEEDED

Test 16

Group: 2, 3

Verdict: TIME LIMIT EXCEEDED

Test 17

Group: 2, 3

Verdict: TIME LIMIT EXCEEDED

Test 18

Group: 2, 3

Verdict: TIME LIMIT EXCEEDED

Test 19

Group: 2, 3

Verdict: ACCEPTED

Test 20

Group: 2, 3

Verdict: ACCEPTED

Test 21

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 22

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 23

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 24

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 25

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 26

Group: 3

Verdict: TIME LIMIT EXCEEDED

Test 27

Group: 3

Verdict: ACCEPTED

Test 28

Group: 3

Verdict: ACCEPTED