第一次codeforces竞技结束 #238 Div 2

php中文网
发布: 2016-06-07 15:07:52
原创
1258人浏览过

Little Chris is a huge fan of linear algebra. This time he has been given a homework about the unusual square of a square matrix. The dot product of two integer number vectors x and y of size n is the sum of the products of the correspondi

Little Chris is a huge fan of linear algebra. This time he has been given a homework about the unusual square of a square matrix.

The dot product of two integer number vectors x and y of size n is the sum of the products of the corresponding components of the vectors. Theunusual square of an n?×?n square matrix A is defined as the sum of n dot products. The i-th of them is the dot product of the i-th row vector and the i-th column vector in the matrix A.

Fortunately for Chris, he has to work only in GF(2)! This means that all operations (addition, multiplication) are calculated modulo 2. In fact, the matrix A is binary: each element of A is either 0 or 1. For example, consider the following matrix A:

第一次codeforces竞技结束 #238 Div 2

The unusual square of A is equal to (1·1?+?1·0?+?1·1)?+?(0·1?+?1·1?+?1·0)?+?(1·1?+?0·1?+?0·0)?=?0?+?1?+?1?=?0.

However, there is much more to the homework. Chris has to process q queries; each query can be one of the following:

  1. given a row index i, flip all the values in the i-th row in A;
  2. given a column index i, flip all the values in the i-th column in A;
  3. find the unusual square of A.

To flip a bit value w means to change it to 1?-?w, i.e., 1 changes to 0 and 0 changes to 1.

Given the initial matrix A, output the answers for each query of the third type! Can you solve Chris's homework?

最佳 Windows 性能的顶级免费优化软件
最佳 Windows 性能的顶级免费优化软件

每个人都需要一台速度更快、更稳定的 PC。随着时间的推移,垃圾文件、旧注册表数据和不必要的后台进程会占用资源并降低性能。幸运的是,许多工具可以让 Windows 保持平稳运行。

下载
来源:php中文网
本文内容由网友自发贡献,版权归原作者所有,本站不承担相应法律责任。如您发现有涉嫌抄袭侵权的内容,请联系admin@php.cn
最新问题
开源免费商场系统广告
热门教程
更多>
最新下载
更多>
网站特效
网站源码
网站素材
前端模板
关于我们 免责申明 举报中心 意见反馈 讲师合作 广告合作 最新更新
php中文网:公益在线php培训,帮助PHP学习者快速成长!
关注服务号 技术交流群
PHP中文网订阅号
每天精选资源文章推送

Copyright 2014-2025 https://www.php.cn/ All Rights Reserved | php.cn | 湘ICP备2023035733号