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++14 (GCC 5.4.1) (judge verdict: Accepted)

#include<iostream>

int calc(int x){
    int ret = 0;
    while(x > 0){
        ret += x % 10;
        x /= 10;
    }
    return ret;
}

int main(){
    int N, A, B;
    std::cin >> N >> A >> B;
    long long sum = 0;
    for(int i = 1; i <= N; i++){
        int keta = calc(i);
        if(A <= keta && keta <= B) sum += i;
    }

    std::cout << sum << std::endl;
    return 0;
}