欢迎来到起遇信息学
起遇信息学正处于上线筹建阶段,以下功能已全部开放免费体验: ✅ 完整题库浏览与代码提交评测(C / C++ / Python / Java 等) ✅ 入门到进阶的系列课程试读、作业与考试 ✅ AI 提示、AI 作业分析等智能助教功能 ✅ 赛事模拟与个人能力报告 ✅ 邮箱注册开放 ⏳ 付费课程订阅与微信/支付宝支付通道 ⏳ 手机号登录,微信扫码登录、微信公众号绑定 使用中如遇任何问题,欢迎通过页面底部 **"联系我们"** 与我们沟通。
CF2082A.Binary Matrix
Binary Matrix
A matrix is called binary if all its elements are either or .
Ecrade calls a binary matrix good if the following two properties hold:
- The bitwise XOR of all numbers in each row of matrix is equal to .
- The bitwise XOR of all numbers in each column of matrix is equal to .
Ecrade has a binary matrix of size . He is interested in the minimum number of elements that need to be changed for the matrix to become good.
However, it seems a little difficult, so please help him!
Input
Each test contains multiple test cases. The first line contains the number of test cases (). The description of the test cases follows.
The first line of each test case contains two integers ().
This is followed by lines, each containing exactly characters consisting only of and , describing the elements of Ecrade's matrix.
It is guaranteed that the sum of across all test cases does not exceed .
Output
For each test case, output a single integer, the minimum number of elements that need to be changed.
Note
In the first test case, he needs to change 2 elements to obtain the following matrix $\begin{pmatrix}1&1&0\\1&0&1\\0&1&1\end{pmatrix}$.
In the second test case, he can make no changes to obtain the following matrix $\begin{pmatrix}0&0&0\\0&0&0\\0&0&0\end{pmatrix}$.
In the third test case, he needs to change 3 elements to obtain the following matrix $\begin{pmatrix}1&0&1\\0&0&0\\1&0&1\end{pmatrix}$.
Samples
7
3 3
010
101
010
3 3
000
000
000
3 3
100
010
001
3 3
101
010
000
3 3
000
010
000
1 4
0101
4 1
0
1
0
1
2
0
3
3
1
2
2
在线编程 IDE
建议全屏模式获得最佳体验
| 进入全屏编程 | Alt+E |
| 递交评测 | Ctrl+Enter |
| 注释/取消注释 | Ctrl+/ |
| 缩放字体 | Ctrl+滚轮 |