LA:https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=3714 HDU:http://acm.hdu.edu.cn/showproblem.php?pid=4081 题目大意: 秦始皇要在n个城市之间修筑一条道路使得任意两个城市均可连通.有个道士可以用法力帮忙修一条路.秦始皇希望其他的道路总长B最短且用法术连接的两个城市的人口…

Qin Shi Huang's National Road System HDU - 4081 感觉这道题和hdu4756很像... 求最小生成树里面删去一边E1 再加一边E2 求该边两顶点权值和除以(最小生成树-E1)的最大值 其中(最小生成树-E1)必须是最小的 先跑一遍prim 跑完之后在最小生成树里面dp dp[i][j] = i到j的路径中最大的那条边 最小生成树减去dp[i][j]肯定会最小 代码如下 #include <cstdio> #include <algorithm…

Qin Shi Huang's National Road System Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 1287    Accepted Submission(s): 475 Problem Description During the Warring States Period of ancient China(47…

题意: 秦始皇要在n个城市之间修路,而徐福声可以用法术位秦始皇免费修1条路,每个城市还有人口数,现要求徐福声所修之路的两城市的人口数之和A尽量大,而使n个城市互通需要修的路长B尽量短,从而使得A/B最大.问A/B最大是多少?(1000个城市) 思路: 老徐可免费修得1条路,那么剩下最多也只需要修n-2条路了,这n-2条路要尽量挑短的,而老徐的那条无所谓长短,只要两城人口尽量多即可.这是没有什么贪心策略的,因为老徐所修之路会影响MST的权值之和的大小.穷举所有城市对要O(n*n),再求次MST需要…

题意:对于已知的网络构建道路,使城市两两之间能够互相到达.其中一条道路是可以免费修建的,问需要修建的总长度B与免费修建的道路所连接的两城市的人口之和A的比值A/B最大是多少. 因为是求A/B的最大值,自然A越大,B越小越好.B的最小值是可以用最小生成树算法求解的,但是,由于免费修建一条道路,使得B值<最小生成树的权值和cnt. 于是,就要考虑究竟选择哪条边作为免费修建?只考虑生成树上的边还是全部边都要考虑?仔细想一下,就会发现任何一条边都存在这样的可能性.而A/B的值同时收A.B的影响,即B可以…

Qin Shi Huang's National Road System Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 3843    Accepted Submission(s): 1336 Problem Description During the Warring States Period of ancient China(47…

题目:Qin Shi Huang's National Road System Qin Shi Huang's National Road System Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 2049    Accepted Submission(s): 746 Problem Description During the W…

Qin Shi Huang's National Road System Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) [Problem Description] During the Warring States Period of ancient China(476 BC to 221 BC), there were seven kingdoms in China ---…

[hdu P4081] Qin Shi Huang’s National Road System Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Problem Description During the Warring States Period of ancient China(476 BC to 221 BC), there were seven kingdoms in…

Qin Shi Huang's National Road System                                                                   Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)                                                                …