#include<bits/stdc++.h> using namespace std; #define ll long long #define pi (4*atan(1.0)) #define eps 1e-14 ,M=4e6+,inf=1e9+,mod=1e9+; ; struct is { int x; int pos; }a[N]; int cmp1(is a,is b) { if(a.x!=b.x) return a.x<b.x; return a.pos<b.pos;…

我自己只能想出O( n*3^m )的做法....肯定会T O( nm*2^m )做法: dp( x, s ) 表示考虑了前 x 个商店, 已买的东西的集合为s. 考虑转移 : 先假设我们到第x个商店去, so初始时 dp( x, s) = dp( x-1, s ) + d[x] 然后我们可以对第x个商店做01背包, dp(x, s + {h} ) = min( dp( x, s + {h} ) , dp( x, s) + c[x][h]) ) ( h ∉ s ). 之后我们再比较到第x个商店划不…

完整代码见kaggle kernel 或 Github 比赛页面:https://www.kaggle.com/c/house-prices-advanced-regression-techniques 这个比赛总的情况就是给你79个特征然后根据这些预测房价 (SalePrice),这其中既有离散型也有连续性特征,而且存在大量的缺失值.不过好在比赛方提供了data_description.txt这个文件,里面对各个特征的含义进行了描述,理解了其中内容后对于大部分缺失值就都能顺利插补了. 参加比赛…

本博客是博主在学习了两篇关于 "House Prices: Advanced Regression Techniques" 的教程 (House Prices EDA 和 Comprehensive data exploration with Python )后的总结,重点在于探究如何分析真实数据的分布以及如何对数据进行预处理,同时强化 pandas 和 seaborn 包的操作技巧. 1 了解数据的基本统计信息 利用pandas读取数据: import pandas as pd im…

状压DP/01背包 Orz Gromah 容易发现m的范围很小……只有16,那么就可以状压,用一个二进制数来表示买了的物品的集合. 一种简单直接的想法是:令$f[i][j]$表示前$i$个商店买了状态集合为$j$的商品的最小代价,那么我们转移的时候就需要枚举在第$i$个商店买了哪些商品吗,这样的话带上枚举子集,复杂度就会变成$O(n*3^m)$,并不是我们能够忍受的…… 那么怎么搞呢?我们每次转移的时候,不再枚举子集,而是搞一个类似01背包的东西:(以下来自Gromah) 我们首先令$f[i][…

Stock Prices Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 987    Accepted Submission(s): 397 Problem Description Buy low, sell high. That is what one should do to make profit in the stock ma…

[BZOJ4145][AMPPZ2014]The Prices Description 你要购买m种物品各一件,一共有n家商店,你到第i家商店的路费为d[i],在第i家商店购买第j种物品的费用为c[i][j], 求最小总费用. Input 第一行包含两个正整数n,m(1<=n<=100,1<=m<=16),表示商店数和物品数. 接下来n行,每行第一个正整数d[i](1<=d[i]<=1000000)表示到第i家商店的路费,接下来m个正整数, 依次表示c[i][j](1&…

洛谷 CF1234A Equalize Prices Again 洛谷传送门 题目描述 You are both a shop keeper and a shop assistant at a small nearby shop. You have nn goods, the ii -th good costs a_i*a**i* coins. You got tired of remembering the price of each product when customers ask fo…

链接: https://codeforces.com/contest/1234/problem/A 题意: You are both a shop keeper and a shop assistant at a small nearby shop. You have n goods, the i-th good costs ai coins. You got tired of remembering the price of each product when customers ask fo…

There are n products in the shop. The price of the ii-th product is aiai. The owner of the shop wants to equalize the prices of all products. However, he wants to change prices smoothly. In fact, the owner of the shop can change the price of some pro…