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 Go (1.14.1) (judge verdict: Accepted)

package main

import (
	"bufio"
	"fmt"
	"io"
	"os"
	"strconv"
	"strings"
)

func main() {
	sc = initScanner(os.Stdin)
	n, a, b := scanInt(sc), scanInt(sc), scanInt(sc)
	fmt.Println(resolve(n, a, b))
}

func resolve(n, a, b int) int {
	var tmp, sum int
	for i := 1; i <= n; i++ {
		tmp = 0
		is := strings.Split(strconv.Itoa(i), "")
		for _, v:= range is {
			vi, _ := strconv.Atoi(v)
			tmp += vi
		}
		if a <= tmp && tmp <= b {
			sum += i
		}
	}

	return sum
}

// --------------- BASE DEFINITIONS ---------------

const (
	initialBufSize = 100000
	maxBufSize     = 1000000
)

var sc *bufio.Scanner

func initScanner(r io.Reader) *bufio.Scanner {
	buf := make([]byte, initialBufSize)

	sc := bufio.NewScanner(r)
	sc.Buffer(buf, maxBufSize)
	sc.Split(bufio.ScanWords)
	return sc
}

func scanInt(sc *bufio.Scanner) int {
	sc.Scan()
	i, _ := strconv.Atoi(sc.Text())
	return i
}

func scanIntSlice(sc *bufio.Scanner, n int) []int {
	is := make([]int, n)
	for i := 0; i < n; i++ {
		is[i] = scanInt(sc)
	}

	return is
}

func scanString(sc *bufio.Scanner) string {
	sc.Scan()
	return sc.Text()
}

func scanStringSlice(sc *bufio.Scanner, n int) []string {
	ss := make([]string, n)
	for i := 0; i < n; i++ {
		sc.Scan()
		ss[i] = sc.Text()
	}

	return ss
}