For problem statement at 0-999/100-199/130-139/134/problemA.txt this is a correct solution, but verifier at 0-999/100-199/130-139/134/verifierA.go ends with All tests passed can you fix the verifier? package main

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

func nextInt(data []byte, idx *int) int {
	n := len(data)
	for *idx < n && (data[*idx] < '0' || data[*idx] > '9') {
		*idx++
	}
	val := 0
	for *idx < n && data[*idx] >= '0' && data[*idx] <= '9' {
		val = val*10 + int(data[*idx]-'0')
		*idx++
	}
	return val
}

func main() {
	data, _ := io.ReadAll(os.Stdin)
	idx := 0
	n := nextInt(data, &idx)
	a := make([]int, n)
	var sum int64
	for i := 0; i < n; i++ {
		a[i] = nextInt(data, &idx)
		sum += int64(a[i])
	}

	ans := make([]int, 0)
	for i := 0; i < n; i++ {
		if int64(a[i])*int64(n) == sum {
			ans = append(ans, i+1)
		}
	}

	out := bufio.NewWriter(os.Stdout)
	defer out.Flush()

	fmt.Fprintln(out, len(ans))
	if len(ans) > 0 {
		var b strings.Builder
		for i, v := range ans {
			if i > 0 {
				b.WriteByte(' ')
			}
			fmt.Fprint(&b, v)
		}
		fmt.Fprintln(out, b.String())
	}
}