给你一个n*m的矩阵,每个点为'B'或'W'或'.'.然后你有一种碎片.碎片可以旋转,问可否用这种碎片精确覆盖矩阵.N,M<=500 WB  <==碎片 W 题目一看,感觉是精确覆盖(最近被覆盖洗脑了),但是仔细分析可以知道,DLX精确覆盖不是正解.因为N*M=250,000远超出DLX的可行规模(数百吧,我猜). 然后感觉是贪心或者是抑或的什么的.... 看了别人的代码,发现是最大匹配...然后就想....对哦=.=其实黑点连2个白点就是匹配呀.... 不得不说网络流构图还是挺有趣的,如果你…

一开始用的STL一直超时不能过,后来发现AC的代码基本都用的普通邻接表,然后改了一下13s,T=T,效率太低了.然后把某大神,详情戳链接http://acm.hust.edu.cn/vjudge/problem/viewSource.action?id=1199083的300+ms的代码加上自己的优化成功到了85ms,限时30s的程序还是挺有成就感的. 题目分析: 一个黑格子要和相邻的两个白格子构成一块,也就是成直角形状,因此,每个黑块必须和相邻上下白块中的一个匹配,同样左右白块必须也有一个和它…

https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=3914 对L研究可以发现 相当于黑-横白,黑-纵白,每个黑白都要被匹配到,其中黑的横纵各两次, 很自然的想到拆点,黑点拆成专门和横白连接的,专门和纵白连接的, 如果2*黑==白数,运行一次二分匹配算法,匹配数==白数则为可行,剩下的都不可行 #include <cstdi…

UVALive - 3942 Remember the Word Neal is very curious about combinatorial problems, and now here comes a problem about words. Know- ing that Ray has a photographic memory and this may not trouble him, Neal gives it to Jiejie. Since Jiejie can’t remem…

UVAlive 3942 Remember the Word 题目: Remember the Word   Time Limit: 3000MS   Memory Limit: Unknown   64bit IO Format: %lld & %llu Submit Status Description Neal is very curious about combinatorial problems, and now here comes a problem about words. Kn…

UVALive - 4108 SKYLINE Time Limit: 3000MS     64bit IO Format: %lld & %llu Submit Status uDebug Description   The skyline of Singapore as viewed from the Marina Promenade (shown on the left) is one of the iconic scenes of Singapore. Country X would a…

UVALive - 3942 Remember the Word A potentiometer, or potmeter for short, is an electronic device with a variable electric resistance. It has two terminals and some kind of control mechanism (often a dial, a wheel or a slide) with which the resistance…

http://vjudge.net/problem/viewProblem.action?id=37480 East Central Regional Contest Problem C: Hexagon Perplexagon A well known puzzle consists of hexagonal pieces, each with the numbers through printed on the sides. Each piece has a different arrang…

Wei Qing (died 106 BC) was a military general of the Western Han dynasty whose campaigns against the Xiongnu earned him great acclaim. He was a relative of Emperor Wu because he was the younger half-brother of Empress Wei Zifu (Emperor Wu’s wife) and…

题目连接: https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=4896 We want to have a great SWERC at Porto this year and we approached this challenge in several ways.We even framed it as a word add…