For problem statement at 1000-1999/1300-1399/1380-1389/1381/problemA1.txt this is a correct solution, but verifier at 1000-1999/1300-1399/1380-1389/1381/verifierA1.go ends with All 66 tests passed can you fix the verifier? package main

import (
	"bufio"
	"fmt"
	"os"
)

func flip(c byte) byte {
	if c == '0' {
		return '1'
	}
	return '0'
}

func apply(s []byte, k int) {
	for i := 0; i < k/2; i++ {
		x := flip(s[i])
		y := flip(s[k-1-i])
		s[i], s[k-1-i] = y, x
	}
	if k%2 == 1 {
		m := k / 2
		s[m] = flip(s[m])
	}
}

func main() {
	in := bufio.NewReader(os.Stdin)
	out := bufio.NewWriter(os.Stdout)
	defer out.Flush()

	var t int
	fmt.Fscan(in, &t)
	for ; t > 0; t-- {
		var n int
		var a, b string
		fmt.Fscan(in, &n)
		fmt.Fscan(in, &a)
		fmt.Fscan(in, &b)

		s := []byte(a)
		ops := make([]int, 0, 2*n)

		for i := n - 1; i >= 0; i-- {
			if s[i] == b[i] {
				continue
			}
			if s[0] == b[i] {
				ops = append(ops, 1)
				s[0] = flip(s[0])
			}
			ops = append(ops, i+1)
			apply(s, i+1)
		}

		fmt.Fprint(out, len(ops))
		for _, v := range ops {
			fmt.Fprint(out, " ", v)
		}
		fmt.Fprintln(out)
	}
}