Two Famous Companies Time Limit: 15000ms Memory Limit: 32768KB This problem will be judged on HDU. Original ID: 425364-bit integer IO format: %I64d      Java class name: Main   In China, there are two companies offering the Internet service for the p…

[题意]:给出n个点,m条边,边分为两种,一种是A公司的,一种是B公司的.边上有权值,问用n-1条边把n个点连起来的最小费用是多少,其中A公司的边刚好有k条.题目保证有解. 思路:我们发现,如果我们给白边增加权值,做最小生成树,由于白边权值增大,导致不容易选白边.记f(x)为给白边增加x权值,做最小生成树后,选白边的数量,可以发现,f(x)随x增大而减小.所以可以二分x 首先,直接做MST的话白色边的数量是无法估计的.可能比要求的多,也可能更少 所以考虑怎样调整白色边的数量 通过这个思路,可以想…

题目意思:给出n个点,m条边,边分为两种,一种是A公司的,一种是B公司的.边上有权值, 问用n-1条边把n个点连起来的最小费用是多少,其中A公司的边刚好有k条.题目保证有解. 题解:题目意思很简单就是求MST且A公司要有且仅有k条边在树中,刚开始做的时候用贪心的方式求 最小生成树结果WA,后来看了下别人的题解,二分出一个最大值delta使得A公司的边加上这个值后再 求MST时A公司的边有大于等于k条,然后答案就是cost of MST - k * delta.思想就是用一个delta去 逼近答案…

Description In China, there are two companies offering the Internet service for the people from all cities: China Telecom and China Unicom. They both are planning to build cables between cities. Obviously, the government wants to connect all the citi…

题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=4255 A Famous Grid Description Mr. B has recently discovered the grid named "spiral grid".Construct the grid like the following figure. (The grid is actually infinite. The figure is only a small par…

The Famous Clock Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1399    Accepted Submission(s): 940 Problem Description Mr. B, Mr. G and Mr. M are now in Warsaw, Poland, for the 2012's ACM-ICPC…

The Famous ICPC Team Again Problem Description   When Mr. B, Mr. G and Mr. M were preparing for the 2012 ACM-ICPC World Final Contest, Mr. B had collected a large set of contest problems for their daily training. When they decided to take training, M…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=4249 题目大意:给一个a+b=c的表达式,但是a.b.c中部分位的数字丢失,并用?代替,问有多少种方案使得这个表达式成立. Sample Input 7+1?=1? ?1+?1=22   Sample Output Case 1: 3 Case 2: 1   Hint There are three solutions for the first case: 7+10=17, 7+11=18, 7+…

A Famous Stone Collector Time Limit: 30000/15000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 793    Accepted Submission(s): 292 Problem Description Mr. B loves to play with colorful stones. There are n colors of…

The Famous ICPC Team Again Time Limit: 30000/15000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 1440    Accepted Submission(s): 708 Problem Description When Mr. B, Mr. G and Mr. M were preparing for the 2012 ACM-I…