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…

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…

Codeforces Round #267 (Div. 2) C. George and Job题目链接请点击~ The new ITone 6 has been released recently and George got really keen to buy it. Unfortunately, he didn't have enough money, so George was going to work as a programmer. Now he faced the follow…

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…

E. Kefa and Watch time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output One day Kefa the parrot was walking down the street as he was on the way home from the restaurant when he saw something gli…

dfs一遍,维护当前连续遇到的喵的数量,然后剪枝,每个统计孩子数量判断是不是叶子结点. #include<bits/stdc++.h> using namespace std; ; int a[maxn]; ],to[maxn<<],ect; inline void addEdge(int u,int v) { to[ect] = v; nxt[ect] = head[u]; head[u] = ect++; } int ct[maxn],m,cnt; void dfs(int u…

排序以后枚举尾部.尺取,头部单调,维护一下就好. 排序O(nlogn),枚举O(n) #include<bits/stdc++.h> using namespace std; typedef long long ll; //#define LOCAL ; struct Node { int m,s; void IN(){ scanf("%d%d",&m,&s); } bool operator < (const Node&rh) const {…

http://codeforces.com/contest/754/problem/C C. Vladik and chat time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Recently Vladik discovered a new entertainment — coding bots for social netwo…

链接: https://codeforces.com/contest/1272/problem/D 题意: You are given an array a consisting of n integers. You can remove at most one element from this array. Thus, the final length of the array is n−1 or n. Your task is to calculate the maximum possib…

题目链接:https://codeforces.com/contest/1370/problem/E 题意 给出两个长为 $n$ 的 $01$ 串 $s$ 和 $t$,每次可以选择 $s$ 的一些下标,使字符只在这些下标内循环右移一个单位,问两个字符串相等至少需要循环移动多少次. 题解 无解的情况 两个字符串中的 $01$ 个数不同. 有解的情况 将 $s$ 中同一位置与 $t$ 不同的字符拿出组成一个新字符串,每次操作一定是取这个新字符串 $01010 \dots$ 或 $10101 \dot…