P3147 [USACO16OPEN]262144 题目描述 Bessie likes downloading games to play on her cell phone, even though she doesfind the small touch screen rather cumbersome to use with her large hooves. She is particularly intrigued by the current game she is playing.…

P3147 [USACO16OPEN]262144 题目描述 Bessie likes downloading games to play on her cell phone, even though she doesfind the small touch screen rather cumbersome to use with her large hooves. She is particularly intrigued by the current game she is playing.…

链接: P3147 P3146双倍经验 前言: 今天发现的一道很有意思的DP题 分析: 第一眼以为是区间DP,于是设f[i][j]为从第i个数到第j个数可以合出的最大值,但思考后发现并不能简单合并,并且n的范围也不支持. 于是想贪心,但是贪着贪着发现自己想不出,于是看题解,发现唯一的贪心也被hack了,果然正解不是贪心. 决定放弃. 于是回头重新看题分析,首先根据n的范围分析后可以发现答案范围很小,最大为58,又回到刚开始的区间DP,我们发现其中有三个关键值,左端点,右端点和答案,那么我们可以尝…

P3147 [USACO16OPEN]262144一道非常有趣的游戏,不,题目.当数据水时,可以这样表示状态.f[i][j]表示合并[i,j]区间所能得到的最大值,有点floyed的小味道.if(f[i][k]==f[k+1][j])f[i][j]=max(f[i][k]+1,f[i][j]);不断更新答案.这样需要枚举左右端点和中间点,O(n^3)300以内的数据可以水过.状态的设定直接把dp拉到暴力里去了. #include<iostream> #include<cstdio>…

题目 此题数据范围小的话可以用区间\(DP\),但是该题目的数据范围并不能用区间DP来求解,因此我们考虑优化\(DP\). 每个数的生成一定是由这两个区间 考虑区间DP的弊端是并不知道每个数生成的区间是什么,所以需要枚举,而这枚举的时间就浪费了.因此考虑以区间信息为状态,在找到区间信息里比较好转移的状态,可得: 状态:\(dp[i][j]\)表示能形成\(i\)这个数的连续区间在以\(j\)为左端点时的右端点. 方程:\(dp[i][j]=dp[i-1][dp[i-1][j]]\)意思就是\(i…

注:两道题目题意是一样的,但是数据范围不同,一个为弱化版,另一个为强化版. P3146传送门(弱化版) 思路: 区间动规,设 f [ i ][ j ] 表示在区间 i ~ j 中获得的最大值,与普通区间动规最大的不同在于:只有左区间的最大值等于右区间的最大值时才能够进行转移. AC代码: #include<cstdio> #include<cstring> #include<cmath> #include<algorithm> #include<cst…

https://www.luogu.org/problemnew/show/P3147 此题与上一题完全一样,唯一不一样的就是数据范围; 上一题是248,而这一题是262144; 普通的区间dp表示状态表示法根本存不下, 这时我们就要想另外的状态表示法; #include <bits/stdc++.h> #define read read() #define up(i,l,r) for(int i = (l);i <=(r); i++) using namespace std; int…

P3143 [USACO16OPEN]钻石收藏家Diamond Collector 题目描述 Bessie the cow, always a fan of shiny objects, has taken up a hobby of mining diamonds in her spare time! She has collected \(N\) diamonds (\(N \leq 50,000\) of varying sizes, and she wants to arrange so…

P3143 [USACO16OPEN]钻石收藏家Diamond Collector 题目描述 Bessie the cow, always a fan of shiny objects, has taken up a hobby of mining diamonds in her spare time! She has collected NN diamonds (N \leq 50,000N≤50,000) of varying sizes, and she wants to arrange…

题目描述 Farmer John and his cows are planning to leave town for a long vacation, and so FJ wants to temporarily close down his farm to save money in the meantime. The farm consists of NN barns connected with MM bidirectional paths between some pairs of…