For problem statement at 1000-1999/1700-1799/1790-1799/1791/problemF.txt this is a correct solution, but verifier at 1000-1999/1700-1799/1790-1799/1791/verifierF.go ends with All tests passed can you fix the verifier? package main

import (
	"bufio"
	"bytes"
	"os"
)

type FastScanner struct {
	r *bufio.Reader
}

func NewFastScanner() *FastScanner {
	return &FastScanner{r: bufio.NewReaderSize(os.Stdin, 1<<20)}
}

func (fs *FastScanner) NextInt() int {
	sign, val := 1, 0
	c, err := fs.r.ReadByte()
	for (c < '0' || c > '9') && c != '-' {
		c, err = fs.r.ReadByte()
		if err != nil {
			return 0
		}
	}
	if c == '-' {
		sign = -1
		c, _ = fs.r.ReadByte()
	}
	for c >= '0' && c <= '9' {
		val = val*10 + int(c-'0')
		c, err = fs.r.ReadByte()
		if err != nil {
			break
		}
	}
	if err == nil {
		_ = fs.r.UnreadByte()
	}
	return sign * val
}

func sumDigits(x int) int {
	s := 0
	for x > 0 {
		s += x % 10
		x /= 10
	}
	return s
}

func main() {
	fs := NewFastScanner()
	var out bytes.Buffer

	t := fs.NextInt()
	for ; t > 0; t-- {
		n, q := fs.NextInt(), fs.NextInt()
		a := make([]int, n+2)
		parent := make([]int, n+2)

		for i := 1; i <= n; i++ {
			a[i] = fs.NextInt()
		}

		parent[n+1] = n + 1
		for i := n; i >= 1; i-- {
			if a[i] > 9 {
				parent[i] = i
			} else {
				parent[i] = i + 1
			}
		}

		var find func(int) int
		find = func(x int) int {
			if parent[x] == x {
				return x
			}
			parent[x] = find(parent[x])
			return parent[x]
		}

		for ; q > 0; q-- {
			typ := fs.NextInt()
			if typ == 1 {
				l, r := fs.NextInt(), fs.NextInt()
				for i := find(l); i <= r; i = find(i + 1) {
					a[i] = sumDigits(a[i])
					if a[i] <= 9 {
						parent[i] = find(i + 1)
					}
				}
			} else {
				x := fs.NextInt()
				out.WriteString(itoa(a[x]))
				out.WriteByte('\n')
			}
		}
	}

	w := bufio.NewWriterSize(os.Stdout, 1<<20)
	w.Write(out.Bytes())
	w.Flush()
}

func itoa(x int) string {
	if x == 0 {
		return "0"
	}
	var buf [20]byte
	i := len(buf)
	for x > 0 {
		i--
		buf[i] = byte('0' + x%10)
		x /= 10
	}
	return string(buf[i:])
}