## Palindromic Indices solution codeforces

You are given a palindromic string ss of length nn.

You have to count the number of indices ii (1≤i≤n)(1≤i≤n) such that the string after removing sisi from ss still remains a palindrome.

For example, consider ss = “aba”

- If we rem ove s1s1 from ss, the string becomes “ba” which is not a palindrome.
- If we remove s2s2 from ss, the string becomes “aa” which is a palindrome.
- If we remove s3s3 from ss, the string becomes “ab” which is not a palindrome.

A palindrome is a string that reads the same backward as forward. For example, “abba“, “a“, “fef” are palindromes whereas “codeforces“, “acd“, “xy” are not.

## Palindromic Indices solution codeforces

- Contestants ranked
**1st**will win a Apple HomePod mini - Contestants ranked
**2nd**will win a Logitech G903 LIGHTSPEED Gaming Mouse - Contestants ranked
**3rd ~ 5th**will win a LeetCode Backpack - Contestants ranked
**6th ~ 10th**will win a LeetCode water bottle - Contestants ranked
**11th ~ 20th**will win a LeetCode Big O Notebook

The input consists of multiple test cases. The first line of the input contains a single integer tt (1≤t≤103)(1≤t≤103) — the number of test cases. Description of the test cases follows.

The first line of each testcase contains a single integer nn (2≤n≤105)(2≤n≤105) — the length of string ss.

The second line of each test case contains a string ss consisting of lowercase English letters. It is guaranteed that ss is a palindrome.

It is guaranteed that sum of nn over all test cases does not exceed 2⋅1052⋅105.

For each test case, output a single integer — the number of indices ii (1≤i≤n)(1≤i≤n) such that the string after removing sisi from ss still remains a palindrome.

## Palindromic Indices solution codeforces

3 3 aba 8 acaaaaca 2 dd

1 4 2

The first test case is described in the statement.

In the second test case, the indices ii that result in palindrome after removing sisi are 3,4,5,63,4,5,6. Hence the answer is 44.

In the third test case, removal of any of the indices results in “d” which is a palindrome. Hence the answer is 22.