感慨一下,区域赛的题目果然很费脑啊!!不过确实是一道不可多得的好题目!! 题目大意:给你一棵有n个节点的树,让你移动树中一条边的位置,即将这条边连接到任意两个顶点(边的大小不变),要求使得到的新树的直径最小. 解题思路:此题先求出原始树的直径maxr1,并记录直径上的各个节点.很容易想到要移动的边一定是直径上的边,只有这样才有可能使树的直径减小!! 接着就是枚举直径上的每条边,并用这条边作为分隔将原始树分割成两棵子树(即子树一和子树二),然后分别求子树一的直径maxr2 和子树二的直径maxr3…

Description You are given an undirected graph with N vertexes and M edges. Every vertex in this graph has an integer value assigned to it at the beginning. You're also given a sequence of operations and you need to process them as requested. Here's a…

Sum of divisors Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 4318    Accepted Submission(s): 1382 Problem Description mmm is learning division, she's so proud of herself that she can figure…

WHUgirls Time Limit: 3000/2000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others) Total Submission(s): 2068    Accepted Submission(s): 785 Problem Description There are many pretty girls in Wuhan University, and as we know, every girl lo…

Description Aliens on planet Pandora also write computer programs like us. Their programs only consist of capital letters (‘A’ to ‘Z’) which they learned from the Earth. On planet Pandora, hackers make computer virus, so they also have anti-virus sof…

Problem Description City C is really a nightmare of all drivers for its traffic jams. To solve the traffic problem, the mayor plans to build a RTQS (Real Time Query System) to monitor all traffic situations. City C is made up of N crossings and M roa…

Description Plain of despair was once an ancient battlefield where those brave spirits had rested in peace for thousands of years. Actually no one dare step into this sacred land until the rumor that “there is a huge gold mine underneath the plain” s…

Problem Description Josh Lyman is a gifted painter. One of his great works is a glass painting. He creates some well-designed lines on one side of a thick and polygonal glass, and renders it by some special dyes. The most fantastic thing is that it c…

意甲冠军:给定的长度可达1000数的顺序,图像password像锁.可以上下滑动,同时会0-9周期. 每个操作.最多三个数字连续操作.现在给出的起始序列和靶序列,获得操作的最小数量,从起始序列与靶序列. 花了一天的时间.我觉得是道非常难的DP.这个阶段非常好划分,对于前面完毕的password锁就不再考虑.问题的关键是这个旋转每次能够的情况非常多. 同一时候也能够发现当I位置上确定移好后,至多影响到后两位.-> dp[i][j][k] 表示当前i位移好后,i+1 为j ,  i+2为k 的次数.…

Problem Description In this problem, you are given several strings that contain only digits from '0' to '9', inclusive.An example is shown below.101123The set S of strings is consists of the N strings given in the input file, and all the possible sub…