codeforces#P1827C. Palindrome Partition
Palindrome Partition
Description
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 $s$.
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 $5\cdot 10^5$.
For each test case print the number of beautiful substrings.
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.
6
6
abaaba
1
a
2
aa
6
abcdef
12
accabccbacca
6
abbaaa
3
0
1
0
14
6
Note
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".