Information Disturbing Time Limit: 3000ms Memory Limit: 65536KB This problem will be judged on HDU. Original ID: 358664-bit integer IO format: %I64d      Java class name: Main   In the battlefield , an effective way to defeat enemies is to break thei…

Information Disturbing Problem Description   In the battlefield , an effective way to defeat enemies is to break their communication system.The information department told you that there are n enemy soldiers and their network which have n-1 communica…

Information Disturbing Time Limit: 6000/3000 MS (Java/Others)    Memory Limit: 131072/65536 K (Java/Others)Total Submission(s): 3205    Accepted Submission(s): 1137 Problem Description In the battlefield , an effective way to defeat enemies is to bre…

HDU - 3586 Information Disturbing 题目大意:从敌人司令部(1号节点)到前线(叶子节点)的通信路径是一个树形结构,切断每条边的联系都需要花费w权值,现在需要你切断前线和司令部的连接,(就是所有叶子节点都到不了根节点),并且总花费不能超过m.问能够实行的方案中,最大花费的最小值,否则输出-1. 树形dp的题还是很好意识到用树形dp的,但最好是画一画图进行理解和推导,就像现在我随手画的图(第一次发现可以传图片). (画得有点小丑,问题不大) 现在回到问题,就是我们需要…

题目描述 Information DisturbingTime Limit: 6000/3000 MS (Java/Others) Memory Limit: 131072/65536 K (Java/Others)Total Submission(s): 4003 Accepted Submission(s): 1391 Problem DescriptionIn the battlefield , an effective way to defeat enemies is to break…

Problem Description In the battlefield , an effective way to defeat enemies is to break their communication system.The information department told you that there are n enemy soldiers and their network which have n-1 communication routes can cover all…

题目大概说一棵树有边权,要删掉一些边,使叶子到达不了树根1且删掉边的权和小于等于m,问删掉边中最大权的最小值能是多少. 考虑问题规模,与转移的时间复杂度,用这么个状态dp: dp[u][k]表示在u结点为根的子树中,使其叶子到达不了根的,删掉边的最大权小于等于k的最小被删边权和 转移略蛋疼,初始值的设定之类的感觉有点不统一..反正最后感觉自己写得有点挫.. #include<cstdio> #include<cstring> #include<algorithm> us…

题意:给出一颗数,1结点代表司令部,叶子节点代表前线,边全值代表花费,然后需要在某些边放置一些炸弹,炸弹的能量不能小于该边的费用,且炸掉的总费用不能超过m问炸弹能力最小多少, 分析dfs+二分,二分枚举下限,费用小于mid的可以炸掉,不能通过,且没有点可以到达叶子节点 #include"stdio.h" #include"string.h" #include"queue" #include"vector" #define M…

题目大意:一棵有n个节点的有根树,1为根节点,边带权,表示删掉这条边的代价.现在要删掉一些边,使叶子节点不能到达根节点.但是,每次删除的边的代价不能超过limit,删掉的边的总代价不能超过m,求最小的limit的可能取值. 题目分析:二分枚举limit,定义状态dp(u)表示将u与它管辖的叶子节点失去联系所需要的总代价,则: dp(u)+=min(dp(son),e[i].w),e[i].w<=limit: dp(u)+=dp(son)  e[i].w>limit: 代码如下: # inclu…

题目链接:http://acm.hdu.edu.cn/showproblem.php?pid=3586 给定n个敌方据点,1为司令部,其他点各有一条边相连构成一棵树,每条边都有一个权值cost表示破坏这条边的费用,叶子节点为前线.现要切断前线和司令部的联系,每次切断边的费用不能超过上限limit,问切断所有前线与司令部联系所花费的总费用少于m时的最小limit.1<=n<=1000,1<=m<=10^6 dp[i]表示i节点为root的这个子树所破坏的最少费用,if(cost[i]…