贪心算法 Heidi and Library (easy)
2 seconds
256 megabytes
standard input
standard output
Your search for Heidi is over – you finally found her at a library, dressed up as a human. In fact, she has spent so much time there that she now runs the place! Her job is to buy books and keep them at the library so that people can borrow and read them. There are n different books, numbered 1 through n.
We will look at the library's operation during n consecutive days. Heidi knows in advance that on the i-th day (1 ≤ i ≤ n) precisely one person will come to the library, request to borrow the book ai, read it in a few hours, and return the book later on the same day.
Heidi desperately wants to please all her guests, so she will make sure to always have the book ai available in the library on the i-th day. During the night before the i-th day, she has the option of going to the bookstore (which operates at nights to avoid competition with the library) and buying any book for the price of 1 CHF. Of course, if she already has a book at the library, she does not need to buy it again. Initially, the library contains no books.
There is a problem, though. The capacity of the library is k – this means that at any time, there can be at most k books at the library. If buying a new book would cause Heidi to have more than k books, she must first get rid of some book that she already has, in order to make room for the new book. If she later needs a book that she got rid of, she will need to buy that book again.
You are given k and the sequence of requests for books a1, a2, ..., an. What is the minimum cost (in CHF) of buying new books to satisfy all the requests?
The first line of input will contain two integers n and k (1 ≤ n, k ≤ 80). The second line will contain n integers a1, a2, ..., an(1 ≤ ai ≤ n) – the sequence of book requests.
On a single line print the minimum cost of buying books at the store so as to satisfy all requests.
4 80
1 2 2 1
2
4 1
1 2 2 1
3
4 2
1 2 3 1
3
In the first test case, Heidi is able to keep all books forever. Therefore, she only needs to buy the book 1 before the first day and the book2 before the second day.
In the second test case, she can only keep one book at a time. Therefore she will need to buy new books on the first, second and fourth day.
In the third test case, before buying book 3 on the third day, she must decide which of the books 1 and 2 she should get rid of. Of course, she should keep the book 1, which will be requested on the fourth day.
#include<iostream>
#include<cstdio>
#include<cmath>
#include<cstring>
#include<sstream>
#include<algorithm>
#include<queue>
#include<deque>
#include<iomanip>
#include<vector>
#include<cmath>
#include<map>
#include<stack>
#include<set>
#include<fstream>
#include<memory>
#include<list>
#include<string>
using namespace std;
typedef long long LL;
typedef unsigned long long ULL;
#define MAXN 88
#define MOD 1000000
#define INF 1000000009
#define eps 0.00000001
/*
贪心策略错误!每次需要去掉元素的时候,不是去掉以后出现次数最多的元素,
去掉下一次出现位置最晚的元素!这个元素占用图书馆空间的时间最长!
*/
int cnt[MAXN], a[MAXN], pos[MAXN];
int n, k;
int main()
{
scanf("%d%d", &n, &k);
for (int i = ; i < n; i++)
{
scanf("%d", &a[i]);
}
set<int> s;
int tmp = ;
for (int i = ; i < n; i++)
{
if (!s.count(a[i]))
{
if (s.size() == k)
{
int Max = -INF, p = -;
for (auto it = s.begin(); it != s.end(); it++)
{
int j;
for (j = i; j < n; j++)
{
if (a[j] == *it)
{
break;
}
}
if (j > Max)
{
Max = j;
p = *it;
}
}
s.erase(p);
//cout << "::::::::::::::" << p << endl;
}
s.insert(a[i]);
tmp++;
}
}
printf("%d\n", tmp);
}
贪心算法 Heidi and Library (easy)的更多相关文章
- 【贪心】codeforces A. Heidi and Library (easy)
http://codeforces.com/contest/802/problem/A [题意] 有一个图书馆,刚开始没有书,最多可容纳k本书:有n天,每天会有人借一本书,当天归还:如果图书馆有这个本 ...
- C. Heidi and Library (神奇的网络流)
C. Heidi and Library 题意 有 n 种分别具有价格 b 的书 a ,图书馆里最多同时存放 k 本书,已知接下来 n 天每天都有一个人来看某一本书,如果图书馆里没有则需要购买,问最少 ...
- 1033. To Fill or Not to Fill (25) -贪心算法
题目如下: With highways available, driving a car from Hangzhou to any other city is easy. But since the ...
- 【CF802C】Heidi and Library(网络流)
[CF802C]Heidi and Library(网络流) 题面 CF 洛谷 题解 前面两个Easy和Medium都是什么鬼玩意啊.... 不难发现如果这天的要求就是第\(a_i\)种书的话,那么\ ...
- CF802C Heidi and Library hard 费用流 区间k覆盖问题
LINK:Heidi and Library 先说一下简单版本的 就是权值都为1. 一直无脑加书 然后发现会引起冲突,可以发现此时需要扔掉一本书. 扔掉的话 可以考虑扔掉哪一本是最优的 可以发现扔掉n ...
- 题解-CF802C Heidi and Library (hard)
题面 CF802C Heidi and Library (hard) 有一个大小为 \(k\) 的空书架.有 \(n\) 天和 \(n\) 种书,每天要求书架中有书 \(a_i\).每天可以多次买书, ...
- LeetCode解题记录(贪心算法)(一)
1. 前言 目前得到一本不错的算法书籍,页数不多,挺符合我的需要,于是正好借这个机会来好好的系统的刷一下算法题,一来呢,是可以给部分同学提供解题思路,和一些自己的思考,二来呢,我也可以在需要复习的时候 ...
- 贪心算法(Greedy Algorithm)
参考: 五大常用算法之三:贪心算法 算法系列:贪心算法 贪心算法详解 从零开始学贪心算法 一.基本概念: 所谓贪心算法是指,在对问题求解时,总是做出在当前看来是最好的选择.也就是说,不从整体最优上加以 ...
- 算法导论----贪心算法,删除k个数,使剩下的数字最小
先贴问题: 1个n位正整数a,删去其中的k位,得到一个新的正整数b,设计一个贪心算法,对给定的a和k得到最小的b: 一.我的想法:先看例子:a=5476579228:去掉4位,则位数n=10,k=4, ...
随机推荐
- html5打开摄像头并用canvas模拟拍照
网上很多关于用HTML5打开本地摄像头的文章,但各有瑕疵.根据我自己的亲身体验,我分享一下我用HTML5打开摄像头的经验. 废话不多说,直接看代码. HTML代码: <video id=&quo ...
- Gym - 101972B Arabella Collegiate Programming Contest (2018) B. Updating the Tree 树DFS
题面 题意:T组数据,每次给你1e5个点的树(1为根),每个点有一权值,询问1-n每个节点的子树中, 至少修改几个点的权值(每次都可以任意修改),才能让子树中任意2点的距离==他们权值差的绝对值 无解 ...
- [Swift通天遁地]九、拔剑吧-(11)创建强大的Pinterest风格的瀑布流界面
★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★➤微信公众号:山青咏芝(shanqingyongzhi)➤博客园地址:山青咏芝(https://www.cnblogs. ...
- unittest举例
步骤:1.先导入unittest2.编写一个测试类(继承unittest.TestCase)3.编写测试用例类,一个方法就是一条用例4.加载测试用例,有三种方式:加载测试方法,加载测试类,加载测试模块 ...
- 微信接口本地调试(IIS服务器)
1.下载ngrok,并注册获得token.官网下载地址:https://ngrok.com/ 如果你是在官网下载的,到后面映射域名的时候会要求购买他们的服务. 这里我们用一个国内免费的ngrok服务器 ...
- [Windows Server 2012] Apache+PHP安全设置
★ 欢迎来到[护卫神·V课堂],网站地址:http://v.huweishen.com ★ 护卫神·V课堂 是护卫神旗下专业提供服务器教学视频的网站,每周更新视频. ★ 本节我们将带领大家:Win20 ...
- 仿iphone动态萤火虫锁屏应用安卓源码
该源码是仿iphone动态萤火虫锁屏应用源码,源码SkyLock,这也是最近弄了一款锁屏,苦于市场百般阻拦与锁屏应用数量实在太多,于是将它拿出来开源:废话不多说,希望大家能够希望,更多说明请看下面的吧 ...
- hibernate注解之@Onetomany、@Manytoone、@JoinColumn
@Onetomany用于实体类与数据库表映射中少的一方,请看下面的例子. 假设一个用户只有一种角色,用户和角色是onetomany的关系 用户实体 @Entity @Table(name=" ...
- zxing 生成条形码
private Bitmap Out1DImg() { // 1.设置条形码规格 EncodingOptions encodeOption = new EncodingOptions(); encod ...
- VBA中Option的四种用法
1.Option Explicit.当使用Option Explicit时,必须在模块中的所有过程声明每一个变量,否则会出现语法错误并不能被编译.这样做的好处是,它能消除程序中因为错拼变量名而导致程序 ...