Round Subset 题目链接:http://codeforces.com/problemset/problem/837/D 数据范围:略. 题解: $dp$比较显然. 但是卡空间,有两种方法: 第一种是滚动数组,第二种是反向枚举. 这两种都可以达到:当前更新需要的数组位置仍然是上个版本的数组.…

开始的时候数据范围算错了~ 我以为整个序列 2 和 5 的个数都不超过 70 ~ 一个非常水的 dp code: #include <bits/stdc++.h> #define M 75 #define N 201 #define LL long long using namespace std; void setIO(string s) { string in=s+".in"; string out=s+".out"; freopen(in.c_st…

Let's call the roundness of the number the number of zeros to which it ends. You have an array of n numbers. You need to choose a subset of exactly k numbers so that the roundness of the product of the selected numbers will be maximum possible. Input…

设dp[i][j][k]表示前i个数中选j个并且因子含有k个2的能获得的最多的5的个数 则dp[i][j][k]=max(dp[i-1][j][k],dp[i-1][j-1][k-cnt2]+cnt5) 滚掉一维 #include <iostream> #include <cstring> #include <cstdio> using namespace std; typedef long long ll; int n, m, allcnt, dp[205][1200…

CF837D. Round Subset Let's call the roundness of the number the number of zeros to which it ends. You have an array of n numbers. You need to choose a subset of exactly k numbers so that the roundness of the product of the selected numbers will be ma…

原标题:https://www.facebook.com/hackercup/problems.php?pid=759650454070547&round=344496159068801 题意:给定一颗有根树,在树上下层的节点要给上层节点礼物,根节点的礼物则给慈善会,可是给礼物有个条件就是你不能送你的父节点已经送出的礼物.问满足要求的最少花费. 题解:这个题卡了一段时间,相似于染色问题,能够用树形动态规划求解.由于已知节点个数为N,则我们单个节点的最大花费不会超过log2(N) = 18. 1.…

Problem   Codeforces Global Round 1 - D. Jongmah Time Limit: 3000 mSec Problem Description Input Output Print one integer: the maximum number of triples you can form. Sample Input 10 62 3 3 3 4 4 4 5 5 6 Sample Output 3 题解:动态规划,对这种状态定义不熟悉,主要还是没有发现最优方…

Problem  Codeforces Round #556 (Div. 2) - D. Three Religions Time Limit: 3000 mSec Problem Description Input Output Sample Input 6 8abdabc+ 1 a+ 1 d+ 2 b+ 2 c+ 3 a+ 3 b+ 1 c- 2 Sample Output YESYESYESYESYESYESNOYES 题解:动态规划,意识到这个题是动态规划之后难点在于要优化什么东西,本题…

Codeforces Round #598 (Div. 3)- E. Yet Another Division Into Teams - 动态规划 [Problem Description] 给你\(n\)个数,将其划分为多组,对于每个组定义其\(d\)值为 组内的最大值减最小值,问如何划分使得最终所有组的\(d\)值之和最小.每个组至少要保证有\(3\)个数. [Solution] 将所有值从小到大排序,然后我们知道最多有\(5\)个人划分到同一组中,如果有\(6\)个人,那么划分为两组一定比…

Problem   Educational Codeforces Round 60 (Rated for Div. 2) - D. Magic Gems Time Limit: 3000 mSec Problem Description Input The input contains a single line consisting of 2 integers N and M (1≤N≤10^18, 2≤M≤100). Output Print one integer, the total n…