注意此题,每一个部分都有一个能量值v[i],他移除第i部分所需的能量是v[f[1]]+v[f[2]]+...+v[f[k]],其中f[1],f[2],...,f[k]是与i直接相连(且还未被移除)的部分的编号. 注意题目移除的都是与第i部分直接相连的部分的能量值, 将本题目简化得,只考虑两个点1和2,1和2相连,1的能量值是10,2的能量值是20, 移除绳子时,要保持能量最小,可以移除部分2,这样移除的能量就是与2相连的部分1的能量即是10: 故每次相连两部分都移除能量值大的即可 #includ…

Codeforces Round #437 (Div. 2) codeforces 867 A. Between the Offices(水) 题意:已知白天所在地(晚上可能坐飞机飞往异地),问是否从西雅图飞到旧金山次数更多. 题解:只要判断第一天和最后一天状态即可. #include<cstdio> #include<cstring> #include<algorithm> using namespace std; ; int n; char s[N]; int ma…

题目链接:Codeforces Round #298 (Div. 2) A. Exam An exam for n students will take place in a long and narrow room, so the students will sit in a line in some order. The teacher suspects that students with adjacent numbers (i and i + 1) always studied side…

链接:http://codeforces.com/contest/437/problem/A A. The Child and Homework time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Once upon a time a child got a test consisting of multiple-choice qu…

A. The Child and Toy Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/438/problem/A Description On Children's Day, the child got a toy from Delayyy as a present. However, the child is so naughty that he can't wait to destroy…

题目链接 题意: 给定goal和limit,求1-limit中的若干个数,每一个数最多出现一次,且这些数的lowbit()值之和等于goal,假设存在这种一些数,输出个数和每一个数:否则-1 分析: 先考虑一下比較普通的情况,给一些数,和一个goal,问时候能达到.(最好还是设这些数已经从大到小排序) 考虑能否够贪心,对于当前的数x: 1.之后的数的和能等于x,那么假设x<=goal,显然必须选x: 2.之后的数的和能等于x-1,那么同上(这个情况就是二进制的情况) 3.之后的数的和不包含上述两…

题目链接:http://codeforces.com/problemset/problem/438/D 给你n个数,m个操作,1操作是查询l到r之间的和,2操作是将l到r之间大于等于x的数xor于x,3操作是将下标为k的数变为x. 注意成段更新的时候,遇到一个区间的最大值还小于x的话就停止更新. #include <iostream> #include <cstdio> #include <cstring> using namespace std; typedef __…

D. The Child and Sequence Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/438/problem/D Description At the children's day, the child came to Picks's house, and messed his house up. Picks was angry at him. A lot of important…

B. The Child and Zoo Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/438/problem/B Description Of course our child likes walking in a zoo. The zoo has n areas, that are numbered from 1 to n. The i-th area contains ai animal…

题目链接:http://codeforces.com/contest/979/problem/C 大致题意 给出n个点,有n-1个边将他们链接.给出x,y,当某一路径中出现x....y时,此路不通.路径(u,v)和(v,u)是不同的. 思路:一开始大神是给每个点都用BFS找出能到的点的路径,同时记录搜索的状态,但出了点小问题,估计修正了也回超时,现在给出大神思路,因为不能自己到自己所以点对数肯定是n*(n-1)这是全部的可能,那我们只要找出不可能的情况相减,那就是答案的对不对?这是肯定的,现在我…