E. Cactus   A connected undirected graph is called a vertex cactus, if each vertex of this graph belongs to at most one simple cycle. A simple cycle in a undirected graph is a sequence of distinct vertices v1, v2, ..., vt (t > 2), such that for any i…

A. Team 模拟. B. Magic, Wizardry and Wonders 可以发现\[d=a_1-a_2+a_3-a_4+\cdots\] 那么有\(odd=\lfloor \frac{n+1}{2} \rfloor\)个奇数,\(even=\lfloor \frac{n}{2} \rfloor\)个偶数. 奇数和范围为\[[max(odd,even+d), min(odd\cdot l, even\cdot l + d)]\] 判断有无解,有解则取均值分配下去即可. C. To A…

题目连链接:http://codeforces.com/contest/231 A. Team time limit per test:2 seconds memory limit per test:256 megabytes One day three best friends Petya, Vasya and Tonya decided to form a team and take part in programming contests. Participants are usually…

题目链接:http://www.codeforces.com/problemset/problem/231/A题意:问n道题目当中有多少道题目是至少两个人会的.C++代码: #include <iostream> using namespace std; int n, a, b, c, ans; int main() { cin >> n; while (n--) { cin >>a >> b >> c; ) ans ++; } cout <…

题目链接:http://codeforces.com/problemset/problem/697/D 给你一个有规则的二叉树,大概有1e18个点. 有两种操作:1操作是将u到v上的路径加上w,2操作是求u到v上的路径和. 我们可以看出任意一个点到1节点的边个数不会超过64(差不多就是log2(1e18)),所以可以找最近相同祖节点的方式写. 用一条边的一个唯一的端点作为边的编号(比如1到2,那2就为这条边的编号),由于数很大,所以用map来存. 进行1操作的时候就是暴力加w至u到LCA(u,v…

E. Famil Door and Roads 题目连接: http://www.codeforces.com/contest/629/problem/E Description Famil Door's City map looks like a tree (undirected connected acyclic graph) so other people call it Treeland. There are n intersections in the city connected b…

Misha, Grisha and Underground time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Misha and Grisha are funny boys, so they like to use new underground. The underground has n stations connected…

Codeforces Round #111 (Div. 2) C. Find Pair 题意 给\(N(N \le 10^5)\)个数,在所有\(N^2\)对数中求第\(K(K \le N^2)\)对数. 排序按照pair比较,first为第一关键字,second第二关键字. 思路 统计\(cnt[x]\)为值\(x\)出现的次数. 第一关键字为\(x\)的对数为\(cnt[x] \times n\),显然可以找到第一关键字. 在确定第一关键字\(x\)后,第二关键字\(y\)的出现次数为\(c…

Codeforces Round #485 (Div. 2) https://codeforces.com/contest/987 A #include<bits/stdc++.h> using namespace std; #define lson l,mid,rt<<1 #define rson mid+1,r,rt<<1|1 #define IT set<ll>::iterator #define sqr(x) ((x)*(x)) #define pb…

Codeforces Round #296 (Div. 1)C. Data Center Drama Time Limit: 2 Sec  Memory Limit: 256 MBSubmit: xxx  Solved: 2xx 题目连接 http://codeforces.com/contest/528/problem/C Description The project of a data center of a Big Software Company consists of n compu…