问题描述:对于给定的一个n个字符组成的字符串s，判断其是否为回文，设字符串s为:

S:”C1,C2,…….Ci,Ci+1,…..Cn”,则对于P=（n/2）,字符串s满足如下条件。

若n为偶数，则有C1=Cn,C2=Cn-1,….,Cp-1=Cp+2,Cp=Cp+1

若n为奇数，则有C1=Cn,C2=Cn-1,….,Cp-1=Cp+3,Cp=Cp+2.

-The descr iption of the problem: given an n-character string s, to determine whether it is a palindrome, set up a string s is: S: C1, C2, .... of Ci, Ci+1, ..... of Cn "　P = (n/2), the string s to meet the following conditions. If n is even, then C1 = Cn, C2 = Cn-1, ...., of Cp 1 = Cp+2 of, Cp = Cp+1　if n is odd, then C1 = Cn, C2 = Cn-1, .... Cp-1 = Cp+3, Cp = Cp+2.