Problem Description
In mathematics, a subsequence is a sequence that can be derived from another sequence by deleting some elements without changing the order of the remaining elements. For example, the sequence
is a subsequence of . (http://en.wikipedia.org/wiki/Subsequence) Given a string S, your task is to find out how many different subsequence of S is palindrome. Note that for any two subsequence X =
and Y = , if there exist an integer i (1<=i<=k) such that xi != yi, the subseq......
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