题目链接 题意: n个点,m条边的森林.q次操作. 每次操作:1.询问x所在树的直径 2.合并x和y所在的树,使得合并后的直径最小 ) 分析: 没有读到图是森林.. .做的好纠结 最開始将每一个树都求一下直径,之后使用并查集处理.每次合并直径:至少是两个树的直径,或者将两个直径的最中间的部分连接求直径 const int MAXN = 310000; int rt[MAXN], ans[MAXN]; VI G[MAXN]; bool vis[MAXN]; void init(int n) { R…
题目传送门 /* 题意:选择a[k]然后a[k]-1和a[k]+1的全部删除,得到点数a[k],问最大点数 DP:状态转移方程:dp[i] = max (dp[i-1], dp[i-2] + (ll) i * cnt[i]); 只和x-1,x-2有关,和顺序无关,x-1不取,x-2取那么累加相同的值,ans = dp[mx] */ #include <cstdio> #include <algorithm> #include <cstring> #include <…
题目传送门 /* DP:从1到最大值,dp[i][1/0] 选或不选,递推更新最大值 */ #include <cstdio> #include <algorithm> #include <cmath> #include <cstring> using namespace std; typedef long long ll; ; const int INF = 0x3f3f3f3f; ll dp[MAXN][]; ll cnt[MAXN]; ll work(…
C. Civilization Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/455/problem/C Description Andrew plays a game called "Civilization". Dima helps him. The game has n cities and m bidirectional roads. The cities are numbe…
题目链接: 题目 C. Civilization time limit per test1 second memory limit per test256 megabytes inputstandard input outputstandard output 问题描述 Andrew plays a game called "Civilization". Dima helps him. The game has n cities and m bidirectional roads. Th…
http://codeforces.com/contest/456/problem/A A. Laptops time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output One day Dima and Alex had an argument about the price and quality of laptops. Dima thi…
D. Serega and Fun Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/455/problem/D Description Serega loves fun. However, everyone has fun in the unique manner. Serega has fun by solving query problems. One day Fedor came up w…
A. Boredom Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/455/problem/A Description Alex doesn't like boredom. That's why whenever he gets bored, he comes up with games. One long winter evening he came up with a game and d…
题目链接:http://codeforces.com/problemset/problem/455/A 给你n个数,要是其中取一个大小为x的数,那x+1和x-1都不能取了,问你最后取完最大的和是多少. 简单dp,dp[i]表示取i时zui最大和为多少,方程为dp[i] = max(dp[i - 1] , dp[i - 2] + cont[i]*i). #include <bits/stdc++.h> using namespace std; typedef __int64 LL; ; LL a…
题目链接:http://codeforces.com/problemset/problem/455/A A. Boredom time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Alex doesn't like boredom. That's why whenever he gets bored, he comes up with…
A. Laptops 题目意思: 给定n台电脑,第i台电脑的价格是ai ,质量是bi ,问是否存在一台电脑价格比某台电脑价格底,但质量确比某台电脑的质量高,即是否存在ai < aj 且 bi > bj ? 解题思路: 这题一定要看题目,a都是1~n的不同数,b也是1~n的不同数,此题只需要判断ai 是否等于bi ,如果ai != bi 的话,则输出“Happy Alex”,如果所有的ai  == bi 则输出“Poor Alex” 证明:先将a按照从小到大排序,当i<j时ai <…
Description Alex doesn't like boredom. That's why whenever he gets bored, he comes up with games. One long winter evening he came up with a game and decided to play it. Given a sequence a consisting of n integers. The player can make several steps. I…
Description Fedya studies in a gymnasium. Fedya's maths hometask is to calculate the following expression: (1n + 2n + 3n + 4n) mod 5 for given value of n. Fedya managed to complete the task. Can you? Note that given number n can be extremely large (e…
Description One day Dima and Alex had an argument about the price and quality of laptops. Dima thinks that the more expensive a laptop is, the better it is. Alex disagrees. Alex thinks that there are two laptops, such that the price of the first lapt…
A. Laptops time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output One day Dima and Alex had an argument about the price and quality of laptops. Dima thinks that the more expensive a laptop is, the…
题目链接 A. Laptops time limit per test:1 secondmemory limit per test:256 megabytesinput:standard inputoutput:standard output One day Dima and Alex had an argument about the price and quality of laptops. Dima thinks that the more expensive a laptop is, t…
B. A Lot of Games Andrew, Fedor and Alex are inventive guys. Now they invent the game with strings for two players. Given a group of n non-empty strings. During the game two players build the word together, initially the word is empty. The players mo…
A. Laptops time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output One day Dima and Alex had an argument about the price and quality of laptops. Dima thinks that the more expensive a laptop is, the…
C. Boredom time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Alex doesn't like boredom. That's why whenever he gets bored, he comes up with games. One long winter evening he came up with a ga…
B. Fedya and Maths time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Fedya studies in a gymnasium. Fedya's maths hometask is to calculate the following expression: (1n + 2n + 3n + 4n) mod 5 f…
D. Serega and Fun time limit per test 4 seconds memory limit per test 256 megabytes input standard input output standard output Serega loves fun. However, everyone has fun in the unique manner. Serega has fun by solving query problems. One day Fedor…
题意(Codeforces-455A) 给你\(n\)个数,你每次可以选择删除去一个数\(x\)获得\(x\)分,但是所有为\(x+1\)和\(x-1\)的数都得删去.问最大获得分数. 分析 这是一条经典dp.阶段是很自然的:我从左往右依次选择到每种数(先预处理在桶内),然后两个决策:拿,还是不拿(拿一定拿光).拿,那么下一步就不能选择\(x+1\)了,直接选择\(x+2\):不拿,我可以选择\(x+1\).两种情况取最大. 于是有状态转移方程:\(dp[x]=max(dp[x-1], dp[x…
Boredom time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Alex doesn't like boredom. That's why whenever he gets bored, he comes up with games. One long winter evening he came up with a game…
#include<iostream> #include<map> #include<string> #include<cstring> #include<cstdio> #include<cstdlib> #include<cmath> #include<queue> #include<vector> #include<algorithm> using namespace std; lo…
A. Laptops time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output One day Dima and Alex had an argument about the price and quality of laptops. Dima thinks that the more expensive a laptop is, the…
D. A Lot of Games time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Andrew, Fedor and Alex are inventive guys. Now they invent the game with strings for two players. Given a group of n non-em…
Codeforces Round #366 (Div. 2) A I hate that I love that I hate it水题 #I hate that I love that I hate it n = int(raw_input()) s = "" a = ["I hate that ","I love that ", "I hate it","I love it"] for i in ran…
Codeforces Round #354 (Div. 2) Problems     # Name     A Nicholas and Permutation standard input/output 1 s, 256 MB    x3384 B Pyramid of Glasses standard input/output 1 s, 256 MB    x1462 C Vasya and String standard input/output 1 s, 256 MB    x1393…
直达–>Codeforces Round #368 (Div. 2) A Brain’s Photos 给你一个NxM的矩阵,一个字母代表一种颜色,如果有”C”,”M”,”Y”三种中任意一种就输出”#Color”,如果只有”G”,”B”,”W”就输出”#Black&White”. #include <cstdio> #include <cstring> using namespace std; const int maxn = 200; const int INF =…
 cf之路,1,Codeforces Round #345 (Div. 2) ps:昨天第一次参加cf比赛,比赛之前为了熟悉下cf比赛题目的难度.所以做了round#345连试试水的深浅.....       其实这个应该是昨天就写完的,不过没时间了,就留到了今天.. 地址:http://codeforces.com/contest/651/problem/A A. Joysticks time limit per test 1 second memory limit per test 256…