E. Alex and Complicated Task time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output After you have read all the problems, probably, you think Alex is genius person. That's true! One day he came u…

原文链接https://www.cnblogs.com/zhouzhendong/p/CF461D.html 题解 首先我们可以发现如果确定了第一行,那么方案就唯一了. 然后,我们来看看一个点的值确定了会导致什么: 假设我们确定了红色点的值,那么所有包含橙色的格子xor起来就等于红色格子的值,绿色蓝色也是. 第一排就比较特殊了. 如果我们在对第一排奇偶分类之后,如果我们可以得到第一行的前缀xor之间的关系,那么我们就有希望解决这个问题. 再看一种情况: 类似地意思,我们会发现这个东西遇到墙会反射…

正题 题目链接:https://www.luogu.com.cn/problem/CF461D 题目大意 \(n*n\)的网格需要填上\(x\)或\(o\),其中有\(k\)个格子已经固定,求有多少中填写方案使得每个格子的四周都有偶数个\(o\). 解题思路 约束条件相当于一个格子周围的异或和都为\(0\),也就是对于任意\((x,y)\)都有\(a_{x-1,y}\ xor\ a_{x,y-1}\ xor\ a_{x+1,y}\ xor\ a_{x,y+1}\).也就是对于一个格子\((x,y…

假设该矩形是aij,那么有a(i,j)=a(i-1,j-1)^a(i-1,j+1)^a(i-2,j),不断递归下去可以发现a(i,j)=a(1,y-x+1)^a(1,y-x+3)^--^a(1,x+y-1). 那么,对第一行处理前缀和,Si=S(i-2)^a(1,i),即给出了两个数S的异或,只需将每一个点裂点为i和i',然后若Si^Sj=0,并查集上连边(i,j)(i',j'),否则连(i,j')(i',j),最后只需判断i和i'是否相连,相连即为0(这个可以理解为i表示i上是1,i'表示i上…

About this Course This course will teach you how to build convolutional neural networks and apply it to image data. Thanks to deep learning, computer vision is working far better than just two years ago, and this is enabling numerous exciting applica…

http://7dot9.com/?p=444 http://whydoidoit.com/2012/08/20/unity-serializer-mono-and-trampolines/ 确定具体原因 那么好吧,打一个测试版本再来看,然后再等着崩溃,查看崩溃日志吧,最终看到的崩溃日志中,崩溃线程输出信息如下: Thread 27 Crashed: 0 libsystem_kernel.dylib 0x38e671fc __pthread_kill + 8 1 libsystem_pthrea…

Ilya got tired of sports programming, left university and got a job in the subway. He was given the task to determine the escalator load factor. Let's assume that n people stand in the queue for the escalator. At each second one of the two following…

D. Ilya and Escalator time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Ilya got tired of sports programming, left university and got a job in the subway. He was given the task to determine…

http://codeforces.com/contest/461 A.水题 B.太挫了,竟然被hack了一发.... C.贪心..竟然没看出来时哈夫曼编码问题 D.题目大意:给一棵树,每一个点为白色或黑色,切断一些边,使得每一个连通块有且仅有一个黑点,问划分方案数. 树形DP, 设状态: dp[v][0]表示以v为根的子树中没有黑点,dp[v][1]有一个黑点. 状态方程: dp[v][1] = dp[v][1]*dp[son][0] + dp[v][0]*dp[son][1] + dp[v]…

Contents Tutorial Hello, World Command-Line Arguments Finding Duplicate Lines A Web Server Loose Ends Program Structure Names Declarations Variables Assignments Type Declarations Packages and Files Scope Basic Data Types Integers Floating-Point Numbe…