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 OCaml (4.02.3) (judge verdict: Accepted)

let () = Scanf.scanf "%d %d %d" @@ fun n a b ->
  Array.init n (fun i ->
    let s = string_of_int @@ i + 1 in
    Array.init (String.length s) (fun i -> Char.code s.[i] - Char.code '0')
    |> Array.fold_left ( + ) 0
    |> (fun n -> if a <= n && n <= b then i + 1 else 0))
  |> Array.fold_left ( + ) 0
  |> Printf.printf "%d\n"