题库练习 XOR Palindromes
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A16257 | XOR Palindromes

时间限制1s
内存限制256MB
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题目描述

You are given a binary string $s$ of length $n$ (a string that consists only of $0$ and $1$ ). A number $x$ is good if there exists a binary string $l$ of length $n$ , containing $x$ ones, such that if each symbol $s_i$ is replaced by $s_i \oplus l_i$ (where $\oplus$ denotes the [bitwise XOR operation](https://en.wikipedia.org/wiki/Bitwise_operation#XOR)), then the string $s$ becomes a palindrome.

You need to output a binary string $t$ of length $n+1$ , where $t_i$ ( $0 \leq i \leq n$ ) is equal to $1$ if number $i$ is good, and $0$ otherwise.

A palindrome is a string that reads the same from left to right as from right to left. For example, 01010, 1111, 0110 are palindromes.

输入格式

Each test contains multiple test cases. The first line contains the number of test cases $t$ ( $1 \le t \le 10^5$ ). The description of the test cases follows.

The first line of each test case contains a single integer $n$ ( $1 \le n \le 10^5$ ).

The second line of each test case contains a binary string $s$ of length $n$ .

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

输出格式

For each test case, output a single line containing a binary string $t$ of length $n+1$ - the answer to the problem.

输入输出样例

输入 #1
5
6
101011
5
00000
9
100100011
3
100
1
1
输出 #1
0010100
111111
0011111100
0110
11
C++ 编辑器
输入
输出