BM88 判断是否为回文字符串
https://www.nowcoder.com/practice/e297fdd8e9f543059b0b5f05f3a7f3b2
func judge( str string ) bool {
for i := 0; i < len(str) / 2; i++ {
if str[i] != str[len(str) - i - 1] {
return false
}
}
return true
}