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 example did, madamimadam, pop that is a palindrome. Try writing an algorithm to determine whether a string is a palindrome.