题目链接: 题目 D. Kefa and Dishes time limit per test:2 seconds memory limit per test:256 megabytes 问题描述 When Kefa came to the restaurant and sat at a table, the waiter immediately brought him the menu. There were n dishes. Kefa knows that he needs exactly…

http://codeforces.com/contest/580/problem/D 题意: 有个人去餐厅吃饭,现在有n个菜,但是他只需要m个菜,每个菜只吃一份,每份菜都有一个欢乐值.除此之外,还有一些规则,x,y,w代表的是如果x吃完后吃y,那么还能获得额外的w欢乐值.计算所能获得的最大欢乐值. 思路: 看到别人说要用状压dp来做,我才恍然大悟啊,感觉自己对于状压dp实在是太不敏感了. d[i][j]表示在当前i状态时最后一份吃的是j的最大欢乐值. 状态转移什么的请看代码吧. #includ…

F. Elongated Matrix 题目链接:https://codeforces.com/contest/1102/problem/F 题意: 给出一个n*m的矩阵,现在可以随意交换任意的两行,最后从上到下,从左到右形成一个序列s1,s2.....snm,满足对于任意相邻的两个数,它们差的绝对值的最大值为k. 现在问怎么交换行与行,可以使得最后的这个k最大. 题解: 人生中第一道状压dp~其实还是参考了这篇博客:https://blog.csdn.net/CSDNjiangshan/art…

题目链接: http://codeforces.com/problemset/problem/401/D D. Roman and Numbers time limit per test4 secondsmemory limit per test512 megabytes 问题描述 Roman is a young mathematician, very famous in Uzhland. Unfortunately, Sereja doesn't think so. To make Sere…

用spfa,和dp是一样的.转移只和最后一个吃的dish和吃了哪些有关. 把松弛改成变长.因为是DAG,所以一定没环.操作最多有84934656,514ms跑过,实际远远没这么多. 脑补过一下费用流,但是限制流量不能保证吃到m个菜 #include<bits/stdc++.h> using namespace std; typedef pair<int,int> nd; typedef long long ll; #define fi first #define se second…

E. Vladik and cards 题目链接 http://codeforces.com/contest/743/problem/E 题面 Vladik was bored on his way home and decided to play the following game. He took n cards and put them in a row in front of himself. Every card has a positive integer number not e…

When Kefa came to the restaurant and sat at a table, the waiter immediately brought him the menu. There were n dishes. Kefa knows that he needs exactly m dishes. But at that, he doesn't want to order the same dish twice to taste as many dishes as pos…

E. Kefa and Watch Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/580/problem/E Description One day Kefa the parrot was walking down the street as he was on the way home from the restaurant when he saw something glittering b…

C. Kefa and Park Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/580/problem/C Description Kefa decided to celebrate his first big salary by going to the restaurant. He lives by an unusual park. The park is a rooted tree con…

B. Kefa and Company Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/580/problem/B Description Kefa wants to celebrate his first big salary by going to restaurant. However, he needs company. Kefa has n friends, each friend wi…