Sorting Slides Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 2831   Accepted: 1076 Description Professor Clumsey is going to give an important talk this afternoon. Unfortunately, he is not a very tidy person and has put all his transpa…

Sorting Slides Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 4469   Accepted: 1766 Description Professor Clumsey is going to give an important talk this afternoon. Unfortunately, he is not a very tidy person and has put all his transpa…

[题目链接] http://poj.org/problem?id=1486 [题目大意] 给出每张幻灯片的上下左右坐标,每张幻灯片的页码一定标在这张幻灯片上, 现在问你有没有办法唯一鉴别出一些幻灯片 [题解] 我们先求一遍匹配,然后对于匹配的边进行删去后再匹配, 如果匹配数量发生变化,则说明这条边不是完美匹配, 测试每一条边之后,我们就能得到完美匹配的边,就是答案. [代码] #include <cstdio> #include <cstring> using namespace…

Description Professor Clumsey is going to give an important talk this afternoon. Unfortunately, he is not a very tidy person and has put all his transparencies on one big heap. Before giving the talk, he has to sort the slides. Being a kind of minima…

题意:找出幻灯片与编号唯一对应的情况 思路: 1:求最大匹配,若小于n,则答案为none,否则转2 (不过我代码没有事先判断一开始的最大匹配数是否<n,但这样也过了,估计给的数据最大匹配数一定为n吧) 2:删除一条边e,以e的一个端点找增广路,若不能找到增广路则e是必须边 也就是重新计算匹配数,如果匹配数减少说明此边是必须也是唯一的.    如果一样说明这边存不存在都行.转3 3:恢复原图,继续步骤2,直到每条边都被删除过 刚开始看网上别人的代码,有一点看不懂,那就是为什么只要找到唯一对应的就输…

题意 给你n个幻灯片,每个幻灯片有个数字编号1~n,现在给每个幻灯片用A~Z进行编号,在该幻灯片范围内的数字都可能是该幻灯片的数字编号.问有多少个幻灯片的数字和字母确定的. 思路 确定幻灯片的数字就是求完美匹配也就是最大匹配,而题目要求的边就是匹配的关键边,也叫必须边,即任意一个最大匹配一定要包含这条边. 关键边求法:先求一遍最大匹配,然后枚举删去匹配边,看之后的最大匹配是否减小,如果减小则该边是匹配关键边. 这让我想起了寻找关键割边:如果一个割边增加流量后整个最大流增加则该割边是关键割边.呵呵…

题意:给你n张照片的范围,n个点的坐标,问你能唯一确定那几个点属于那几张照片,例如样例中4唯一属于A,2唯一属于C,1唯一属于B,3唯一属于C 思路:进行二分图完全匹配,怎么判断唯一属于?匹配完之后删掉某一条匹配边再跑一次二分图匹配,如果还能完全匹配,那么就不是唯一,反之唯一. 代码: #include<set> #include<map> #include<stack> #include<cmath> #include<queue> #incl…

题目大意:有n张幻灯片和n个数字,幻灯片放置有重叠,每个数字隶属于一个幻灯片,现在问你能够确定多少数字一定属于某个幻灯片 思路:上次刷过二分图的必须点后这题思路就显然了 做一次二分匹配后将当前匹配的边删除,再做一次二分匹配,如果能匹配到那么说明这条边不是必须边 顺便说下 删边以后不用从头开始二分匹配,而是在原来二分匹配的基础上对这个点进行增广就行,另外这题格式需要注意,很容易PE #include<cstdio> #include<string.h> #include<ios…

Sorting Slides Time Limit: 1000MS   Memory Limit: 10000K Total Submissions: 5390   Accepted: 2095 Description Professor Clumsey is going to give an important talk this afternoon. Unfortunately, he is not a very tidy person and has put all his transpa…

poj 1094 Sorting It All Out Time Limit:1000MS     Memory Limit:10000KB     64bit IO Format:%lld & %llu Description An ascending sorted sequence of distinct values is one in which some form of a less-than operator is used to order the elements from sm…