For problem statement at 0-999/700-799/730-739/730/problemH.txt this is a correct solution, but verifier at 0-999/700-799/730-739/730/verifierH.go ends with All tests passed can you fix the verifier? package main

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

func match(s string, p []byte) bool {
	if len(s) != len(p) {
		return false
	}
	for i := 0; i < len(p); i++ {
		if p[i] != '?' && p[i] != s[i] {
			return false
		}
	}
	return true
}

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

	var n, m int
	fmt.Fscan(in, &n, &m)

	files := make([]string, n)
	for i := 0; i < n; i++ {
		fmt.Fscan(in, &files[i])
	}

	del := make([]bool, n)
	idx := make([]int, m)
	for i := 0; i < m; i++ {
		fmt.Fscan(in, &idx[i])
		idx[i]--
		del[idx[i]] = true
	}

	base := files[idx[0]]
	l := len(base)
	for i := 1; i < m; i++ {
		if len(files[idx[i]]) != l {
			fmt.Fprintln(out, "No")
			return
		}
	}

	pattern := []byte(base)
	for pos := 0; pos < l; pos++ {
		c := base[pos]
		for i := 1; i < m; i++ {
			if files[idx[i]][pos] != c {
				pattern[pos] = '?'
				break
			}
		}
	}

	for i := 0; i < n; i++ {
		if !del[i] && match(files[i], pattern) {
			fmt.Fprintln(out, "No")
			return
		}
	}

	fmt.Fprintln(out, "Yes")
	fmt.Fprintln(out, string(pattern))
}