Problem:
Score : 200 points

Problem Statement

Find the sum of the integers between 1 and N (inclusive), whose sum of digits written in base 10 is between A and B (inclusive).

Constraints

1 \leq N \leq 10^4

1 \leq A \leq B \leq 36

All input values are integers.

Input

Input is given from Standard Input in the following format:

N A B

Output

Print the sum of the integers between 1 and N (inclusive), whose sum of digits written in base 10 is between A and B (inclusive).

Sample Input 1

20 2 5

Sample Output 1

84

Among the integers not greater than 20, the ones whose sums of digits are between 2 and 5, are: 2,3,4,5,11,12,13,14 and 20. We should print the sum of these, 84.

Sample Input 2

10 1 2

Sample Output 2

13

Sample Input 3

100 4 16

Sample Output 3

4554

Solution in C# (Mono 4.6.2.0) (judge verdict: Wrong Answer)

using System;

class Program
{
    static void Main(string[] args)
    {
        var input = Console.ReadLine().Split(' ');
        var N = int.Parse(input[0]);
        var A = int.Parse(input[1]);
        var B = int.Parse(input[2]);

        var n1 = 0;
        var n2 = 0;
        var n3 = 0;
        var n4 = 0;
        var total = 0;
        var sum = 0;

        for(int i=0; i<=N; ++i)
        {
            if(i<10)
            {
                n1 = i;
            }

            else if(i<100)
            {
                n2 = i/10;
                n1 = i-n2*10;
            }

            else if(i<1000)
            {
                n3 = i/100;
                n2 = (i-(n3*100))/10 ;
                n1 = i-(n3*100)-(n2*10);

            }

            if(i<10001)
            {
                n4 = i/1000;
                n3 = (i-(n4*1000))/100;
                n2 = ((i-(n4*1000)) -(n3*100))/10;
                n1 = ((i-(n4*1000)) -(n3*100)) -(n2*10);
            }

            sum = n4+n3+n2+n1;

            if(A<=sum && sum<=B)
            {
                total += i;
            }
        }
        Console.WriteLine(total);
    }
}