題意：

Problem C. String Magic (Easy Version)

?

Given a string S of length n (indexed from 1 to n) , define f(S) equal to the number of pair (i; j) that:

? 1 <= i < j <= n

? j - i + 1 = 2k; k > 0 (j - i + 1 is even)

? S[i; i + k - 1] = S[i + k; j]

? S[i; i + k - 1] is a palindrome

Here S[L,R] denotes the substring of S with index from L to R.

A palindrome is a string that reads the same from left to right as from right to left.

We need? to calculate f(S).

題解：

主席樹 + 回文串

?

in:

3

aaaa

abaaba

ababa

?

out:

4

2

0?