Codeforces Round 793 (Div. 2)
A
Palindromic Indices
Codeforces
800
原题
←B →
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You are given a palindromic string $s$ of length $n$.

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You have to count the number of indices $i$ $(1 \le i \le n)$ such that the string after removing $s_i$ from $s$ still remains a palindrome.

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For example, consider $s$ = "aba"

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  1. If we remove $s_1$ from $s$, the string becomes "ba" which is not a palindrome.
  2. If we remove $s_2$ from $s$, the string becomes "aa" which is a palindrome.
  3. If we remove $s_3$ from $s$, the string becomes "ab" which is not a palindrome.
翻译中…

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.

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Input

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The input consists of multiple test cases. The first line of the input contains a single integer $t$ $(1 \leq t \leq 10^3)$  — the number of test cases. Description of the test cases follows.

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The first line of each testcase contains a single integer $n$ $(2 \leq n \leq 10^5)$  — the length of string $s$.

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

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It is guaranteed that sum of $n$ over all test cases does not exceed $2 \cdot 10^5$.

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Output

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For each test case, output a single integer  — the number of indices $i$ $(1 \le i \le n)$ such that the string after removing $s_i$ from $s$ still remains a palindrome.

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Note

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The first test case is described in the statement.

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In the second test case, the indices $i$ that result in palindrome after removing $s_i$ are $3, 4, 5, 6$. Hence the answer is $4$.

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In the third test case, removal of any of the indices results in "d" which is a palindrome. Hence the answer is $2$.

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样例

Input #1
3
3
aba
8
acaaaaca
2
dd
Output #1
1
4
2
InputCopy OutputCopy
题目信息
题号
1682A
时间限制
1 s
内存限制
256 MB
标签
贪心
字符串

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。