题目链接: http://codeforces.com/contest/378/problem/E 题意: dota选英雄,现在有n个英雄,m个回合,两支队伍: 每一回合两个选择: b 1,队伍一ban掉一个英雄,或是跳过这个回合 p 1,队伍1选一个英雄 现在每个队伍都是最优决策,问最后队伍一的英雄实力和-队伍二的英雄实力和. 题解: 状压dp,决策要倒过来做,也就是dp出后面回合的决策的基础上设计出对自己当前回合对自己最有利的决策.. 注意:只有top m的英雄有可能被选,其他的都不可能被选…
C. Captains Mode 题目连接: http://codeforces.com/contest/377/problem/C Description Kostya is a progamer specializing in the discipline of Dota 2. Valve Corporation, the developer of this game, has recently released a new patch which turned the balance of…
Hard problem 题目链接: http://codeforces.com/contest/706/problem/C Description Vasiliy is fond of solving different tasks. Today he found one he wasn't able to solve himself, so he asks you to help. Vasiliy is given n strings consisting of lowercase Engl…
D. Developing Game 题目连接: http://www.codeforces.com/contest/377/problem/D Description Pavel is going to make a game of his dream. However, he knows that he can't make it on his own so he founded a development company and hired n workers of staff. Now…
B. Preparing for the Contest 题目连接: http://codeforces.com/contest/377/problem/B Description Soon there will be held the world's largest programming contest, but the testing system still has m bugs. The contest organizer, a well-known university, has n…
A. Maze 题目连接: http://codeforces.com/contest/377/problem/A Description Pavel loves grid mazes. A grid maze is an n × m rectangle maze where each cell is either empty, or is a wall. You can go from one cell to another only if both cells are empty and h…
题目链接:http://codeforces.com/problemset/problem/377/A 题解: 有tot个空格(输入时统计),把其中k个空格变为wall,问怎么变才能使得剩下的空格依然为连通的.把问题反过来,其实就是求tot-k的连通图.dfs:在搜索过的空格中做个标记,同时更新连通个数. 代码如下: #include<cstdio>//hdu3183 CodeForces 377A dfs #include<cstring> #include<cmath&g…
377A Maze 大意: 给定棋盘, 保证初始所有白格连通, 求将$k$个白格变为黑格, 使得白格仍然连通. $dfs$回溯时删除即可. #include <iostream> #include <functional> #include <sstream> #include <algorithm> #include <cstdio> #include <math.h> #include <set> #include &…
D. Developing Game   Pavel is going to make a game of his dream. However, he knows that he can't make it on his own so he founded a development company and hired n workers of staff. Now he wants to pick n workers from the staff who will be directly r…
D - Developing Game 思路:我们先枚举左边界,把合法的都扣出来,那么对于这些合法的来说值有v 和 r两维了,把v, r看成线段的两端, 问题就变成了,最多能选多少线段 使得不存在这样两条(l1 r1)  (l2 r2) l2 > r1,我们把线段l1 r1 看成二维平面内的点(l1, r1) 那么答案就变成了分别在(1, 1),  (2, 2),  (3, 3),  (4, 4), ....., (n, n)的左上的点的个数的最大值,我们用这个建 线段树然后就变成了区间加减问题…
一般这种要倒着来. #include<bits/stdc++.h> #define LL long long #define fi first #define se second #define mk make_pair #define PII pair<int, int> #define y1 skldjfskldjg #define y2 skldfjsklejg using namespace std; ; ; const int inf = 0x3f3f3f3f; cons…
Coloring Trees Problem Description: ZS the Coder and Chris the Baboon has arrived at Udayland! They walked in the park where n trees grow. They decided to be naughty and color the trees in the park. The trees are numbered with integers from 1 to n fr…
题目链接: http://codeforces.com/problemset/problem/268/E E. Playlist time limit per test 1 secondmemory limit per test 256 megabytes 问题描述 Manao's friends often send him new songs. He never listens to them right away. Instead, he compiles them into a play…
题目链接: http://codeforces.com/contest/464/problem/C J. Substitutes in Number time limit per test 1 secondmemory limit per test 256 megabytes 问题描述 Andrew and Eugene are playing a game. Initially, Andrew has string s, consisting of digits. Eugene sends A…
D. Fox And Jumping 题目连接: http://codeforces.com/contest/510/problem/D Description Fox Ciel is playing a game. In this game there is an infinite long tape with cells indexed by integers (positive, negative and zero). At the beginning she is standing at…
B. Maximum Submatrix 2 Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/problemset/problem/375/B Description You are given a matrix consisting of digits zero and one, its size is n × m. You are allowed to rearrange its rows. What is…
题目链接: http://codeforces.com/contest/677/problem/D 题意: 让你求最短的从start->...->1->...->2->...->3->...->...->p的最短路径. 题解: 这题dp的阶段性还是很明显的,相同的值得方格为同一个阶段,然后求从阶段1->2->3...->p的阶段图最短路. 初始化所有a[x][y]==1的格子为起始点到(x,y)坐标的距离. 方程式为dp[x1][y1…
题目链接:http://codeforces.com/problemset/problem/429/B 给你一个矩阵,一个人从(1, 1) ->(n, m),只能向下或者向右: 一个人从(n, 1) ->(1, m),只能向上或者向右.必须有一个相遇点, 相遇点的值不能被取到, 问两个人能得到的最大路径和是多少? dp[i][j]:表示从一个点出发的最大值:先预处理从(1,1) (1,m) (n,1) (n,m)四个点出发的4个dp最大值.然后枚举所有的点,但是这个点不能在边缘,考虑枚举点不够…
B. Strip Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/487/problem/B Description Alexandra has a paper strip with n numbers on it. Let's call them ai from left to right. Now Alexandra wants to split it into some pieces (p…
E. LIS of Sequence Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/486/problem/E Description The next "Data Structures and Algorithms" lesson will be about Longest Increasing Subsequence (LIS for short) of a sequence.…
D. Duff in Beach Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/588/problem/D Description While Duff was resting in the beach, she accidentally found a strange array b0, b1, ..., bl - 1 consisting of l positive integers. Th…
B. Modulo Sum Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/577/problem/B Description You are given a sequence of numbers a1, a2, ..., an, and a number m. Check if it is possible to choose a non-empty subsequence aij such…
http://codeforces.com/contest/459/problem/E 不明确的是我的代码为啥AC不了,我的是记录we[i]以i为结尾的点的最大权值得边,然后wa在第35  36组数据 然后參考答案了,然后----网上一份题解 大意: 给出一个带权有向图,求经过的边权绝对上升的最长路径(可能是非简单路径,就可以能经过一个点多次)所包括的边数. 题解: 对边按权值排序后,从小到大搞. 设q[x]为已经搞过的边组成的以x点为终点的最长路径包括的边数. 设当前边e[i]为从u到v的边,…
题目:http://codeforces.com/problemset/problem/429/B 第一个人初始位置在(1,1),他必须走到(n,m)只能往下或者往右 第二个人初始位置在(n,1),他必须走到(1,m)只能往上或者往右 每个点都有个权值,要求两个人中间相遇一次且只有一次,相遇的那个点的权值不算,两个人的速度可以不一样,然后求出最大值是多少 思路:他的要求是相遇一次且只有一次,那么画几个图其实就只有两个情况了(这图是借了一位大佬的,[小声bb]) 既然知道了这个图分为了这四个区域,…
题目:https://codeforces.com/problemset/problem/711/C 题意:给你n,m,k,代表n个数的序列,有m种颜色可以涂,0代表未涂颜色,其他代表已经涂好了,连着一段是相同颜色的是一个连通块,求正好有k个连通块的最小花费 思路:首先每个位置有可能有m中颜色,而且要满足k个,我们我们可以推出所有情况 dp[n][m][k] n代表前n个数 m代表当前涂m色 k代表满足k个了 #include<cstdio> #include<cmath> #in…
https://codeforces.com/contest/1111/problem/E 题意 一颗有n个点的树,有q个询问,每次从树挑出k个点,问将这k个点分成m组,需要保证在同一组中不存在一个点是另一个点的祖先这种情况,问有多少中分组方案 题解 首先解决转移问题,假设一次询问全颗树的分组方案数,定义dp[u][i]为到树节点u,分了i组的方案数,其中num(fa[u])为u的祖先节点个数 \(dp[u][i]=dp[fa][i]*(i-num(fa[u]))+dp[fa][i-1]\) 当…
B. Dreamoon and WiFi 题目连接: http://www.codeforces.com/contest/476/problem/B Description Dreamoon is standing at the position 0 on a number line. Drazil is sending a list of commands through Wi-Fi to Dreamoon's smartphone and Dreamoon follows them. Eac…
题目链接: http://codeforces.com/problemset/problem/149/D D. Coloring Brackets time limit per test2 secondsmemory limit per test256 megabytes 问题描述 Once Petya read a problem about a bracket sequence. He gave it much thought but didn't find a solution. Toda…
题目链接: https://codeforces.com/contest/166/problem/E 题目: 题意: 给你一个三菱锥,初始时你在D点,然后你每次可以往相邻的顶点移动,问你第n步回到D点的方案数. 思路: 打表找规律得到的序列是0,3,6,21,60,183,546,1641,4920,14763,通过肉眼看或者oeis可以得到规律为. dp计数:dp[i][j]表示在第i步时站在位置j的方案数,j的取值为[0,3],分别表示D,A,B,C点,转移方程肯定是从其他三个点转移. 代码…
D. Alyona and Strings 题目连接: http://www.codeforces.com/contest/682/problem/D Description After returned from forest, Alyona started reading a book. She noticed strings s and t, lengths of which are n and m respectively. As usual, reading bored Alyona…