题目描述
A substring is a continuous and non-empty segment of letters from a given string, without any reorders.
An even palindrome is a string that reads the same backward as forward and has an even length. For example, strings "zz", "abba", "abccba" are even palindromes, but strings "codeforces", "reality", "aba", "c" are not.
A beautiful string is an even palindrome or a string that can be partitioned into some smaller even palindromes.
You are given a string $s$, consisting of $n$ lowercase Latin letters. Count the number of beautiful substrings of $s$.
Input
Each test contains multiple test cases. The first line contains the number of test cases $t$ ($1 \le t \le 10^4$). The description of the test cases follows.
The first line of each test case contains a single integer $n$ ($1 \le n \le 5\cdot 10^5$).
The second line of each test case contains a string $s$. String $s$ consists of only lowercase Latin letters and has a length of $n$.
It is guaranteed that the sum of $n$ over all test cases does not exceed $5\cdot 10^5$.
Output
For each test case print the number of beautiful substrings.
输入格式
见题面 Input 部分
输出格式
见题面 Output 部分
样例输入
样例输出
提示
In the first test case, the beautiful substrings are "abaaba", "baab", "aa".
In the last test case, the beautiful substrings are "aa" (counted twice), "abba", "bb", "bbaa", "abbaaa".