所谓回文，是指从前向后顺读和从后向前倒读都一样的不含空白字符的串。例如did，madamimadam，pop即是回文。试编写一个算法，以判断一个串是否是回文。-The so-called palindrome, is read from front to back and from back to front along the back are the same as reading the string does not contain blank characters. For examp