[快速幂]Codeforces Round #576 (Div. 2)-C. MP3
1 second
256 megabytes
standard input
standard output
One common way of digitalizing sound is to record sound intensity at particular time moments. For each time moment intensity is recorded as a non-negative integer. Thus we can represent a sound file as an array of nn non-negative integers.
If there are exactly KK distinct values in the array, then we need k=⌈log2K⌉k=⌈log2K⌉ bits to store each value. It then takes nknk bits to store the whole file.
To reduce the memory consumption we need to apply some compression. One common way is to reduce the number of possible intensity values. We choose two integers l≤rl≤r, and after that all intensity values are changed in the following way: if the intensity value is within the range [l;r][l;r], we don't change it. If it is less than ll, we change it to ll; if it is greater than rr, we change it to rr. You can see that we lose some low and some high intensities.
Your task is to apply this compression in such a way that the file fits onto a disk of size II bytes, and the number of changed elements in the array is minimal possible.
We remind you that 11 byte contains 88 bits.
k=⌈log2K⌉ is the smallest integer such that K≤2k. In particular, if K=1, then k=0.
The first line contains two integers nn and II (1≤n≤4e5, 1≤I≤1e8) — the length of the array and the size of the disk in bytes, respectively.
The next line contains nn integers aiai (0≤≤ai≤1e9) — the array denoting the sound file.
Print a single integer — the minimal possible number of changed elements.
6 1
2 1 2 3 4 3
2
6 2
2 1 2 3 4 3
0
6 1
1 1 2 2 3 3
2
In the first example we can choose l=2,r=3l=2,r=3. The array becomes 2 2 2 3 3 3, the number of distinct elements is K=2K=2, and the sound file fits onto the disk. Only two values are changed.
In the second example the disk is larger, so the initial file fits it and no changes are required.
In the third example we have to change both 1s or both 3s.
题意:给你n个数,求最少删去多少个数才能满足剩下数的个数的种类小于等于2^(8*I/n),令K是现在数的种类,I是给出的byte,k是由K算出的bit,注意1 byte contains 8 bits,k=log2(K),n*k<=8*I,k<=8*I/n,K<=2^(k)<=2^(8*I/n),所以剩下的数的种类要<=2^(8*I/n)
注意:1 byte contains 8 bits
K<=4e5 -> ->K在int范围内 -> K<=2^(32)-1 rg<=32,不限制这个的话快速幂那会爆long long
要删去最少的数目,而用总数减去剩下的就是要删掉的,剩下的个数的种类是need,可用前缀和求出各种情况下need种数的个数
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int amn=4e5+,inf=0x3f3f3f3f;
int a[amn],b[amn],c[amn];
map<int,int> mp;
ll qp(ll in){ ///快速幂
ll ans=,t=;
while(in){
if(in&)ans*=t;
in>>=;
t*=t;
}
return ans;
}
int main(){
int n,I,tp=;
cin>>n>>I;
ll rg=*I/n; ///k=log2(K),n*k<=8*I,k<=8*I/n
if(rg>32)rg=32;/// K<=4e5 -> ->K在int范围内 -> K<=2^(32)-1 rg<=32,不限制这个的话快速幂那会爆long long
for(int i=1;i<=n;i++){
cin>>a[i];
if(!mp[a[i]]) ///如果a[i]没被统计过
b[++tp]=a[i]; ///统计数有多少种
mp[a[i]]++; ///统计数的个数
}
ll need=qp(rg); ///快速幂计算最后要剩多少个,K<=2^(k)<=2^(8*I/n)
if(tp<=need)printf("0\n");
else{
sort(b+,b++tp); ///区间中从小到大
c[]=;
for(int i=;i<=tp;i++){
c[i]=c[i-]+mp[b[i]]; ///数的个数作前缀和
}
ll ans=inf;
for(int i=;i<=tp-need;i++){
ans=min(ans,(ll)n-(c[i+need]-c[i])); ///要删去最少的数目,而用总数减去剩下的就是要删掉的,剩下的个数的种类是need,可用前缀和求出各种情况下need种数的个数
}
printf("%lld\n",ans);
}
}
[快速幂]Codeforces Round #576 (Div. 2)-C. MP3的更多相关文章
- 线段树+矩阵快速幂 Codeforces Round #373 (Div. 2) E
http://codeforces.com/contest/719/problem/E 题目大意:给你一串数组a,a[i]表示第i个斐波那契数列,有如下操作 ①对[l,r]区间+一个val ②求出[l ...
- Codeforces Round #576 (Div. 2) D. Welfare State
http://codeforces.com/contest/1199/problem/D Examples input1 output1 input2 output2 Note In the firs ...
- Codeforces Round #576 (Div. 1)
Preface 闲来无事打打CF,就近找了场Div1打打 这场感觉偏简单,比赛时艹穿的人都不少,也没有3000+的题 两三个小时就搞完了吧(F用随机水过去了) A. MP3 题意不好理解,没用翻译看了 ...
- Codeforces Round #576 (div.1 + div.2)
Div2 A 长度为\(n(n≤10^5)\)的数组,每个元素不同,求有多少个位置\(d\)满足\(d - x \le j < d \And d < j \le d + y a_d< ...
- Codeforces Round #576 (Div. 1) 简要题解 (CDEF)
1198 C Matching vs Independent Set 大意: 给定$3n$个点的无向图, 求构造$n$条边的匹配, 或$n$个点的独立集. 假设已经构造出$x$条边的匹配, 那么剩余$ ...
- Codeforces Round #576 (Div. 2) 题解
比赛链接:https://codeforc.es/contest/1199 A. City Day 题意:给出一个数列,和俩个整数\(x,y\),要求找到序号最靠前的数字\(d\),使得\(d\)满足 ...
- Codeforces Round #383 (Div. 2) 题解【ABCDE】
Codeforces Round #383 (Div. 2) A. Arpa's hard exam and Mehrdad's naive cheat 题意 求1378^n mod 10 题解 直接 ...
- Codeforces Round #113 (Div. 2)
Codeforces Round #113 (Div. 2) B. Polygons 题意 给一个\(N(N \le 10^5)\)个点的凸包 \(M(M \le 2 \cdot 10^4)\)次询问 ...
- Codeforces Round #373 (Div. 1)
Codeforces Round #373 (Div. 1) A. Efim and Strange Grade 题意 给一个长为\(n(n \le 2 \times 10^5)\)的小数,每次可以选 ...
随机推荐
- array, matrix, list and dataframe
总结一下"入门3R"(Reading, 'Riting, 'Rrithmetic)中的读和写,不同的数据结构下的读写还是有点区别的. vector 命名 12 month.days ...
- rpmbuild 实践
安装 rpmbuild 1 # yum install -y rpm-build 查看 rpmbuild 相关的宏和参数 12345678 # rpmbuild --showrc | grep --c ...
- C++走向远洋——48(项目一1、复数类中的运算符重载、类的成员函数)
*/ * Copyright (c) 2016,烟台大学计算机与控制工程学院 * All rights reserved. * 文件名:text.cpp * 作者:常轩 * 微信公众号:Worldhe ...
- swoole(3)网络服务模型(单进程阻塞、预派生子进程、单进程阻塞复用模型)
一:单进程阻塞 设计流程: 创建一个socket,绑定端口bind,监听端口listen 进入while循环,阻塞在accept操作上,等待客户端连接进入,进入睡眠状态,直到有新的客户发起connet ...
- 1,Java知识储备
1,关于 . java文件 规定:第一行为 package name; 表示该.java文件属于哪一个包. 一个.java文件中可以有多个类,但是只能有一个public类,并且这个public类必须与 ...
- Centos +Docker 安装及仓库使用概述
1. Linux 系统学习Docker安装篇 这里我使用的Centos系统 安装Docker yum命令说明 即Yellowdog Update Modifier,是一种基于rpm的包管理工具 yu ...
- idea 报Сannot Run Git runnerw.exe: AttachConsole failed with error 6
报错:Сannot Run Git runnerw.exe: AttachConsole failed with error 6 解决方案:指向Git 的git.exe文件所在的安装目录,配置上就可以 ...
- java调用DLL,打印二维码标签
package com.ian.das.controller; import java.util.List; import org.xvolks.jnative.JNative; import org ...
- docker 搭建本地私有仓库
1.使用registry镜像创建私有仓库 安装docker后,可以通过官方提供的 registry 镜像来简单搭建一套本地私有仓库环境: docker run -d -p : registry: 这将 ...
- 什么是data:image/png;base64,?一道关于Data URI Scheme的入门级CTF_Web题
一道关于Data URI Scheme的入门级CTF_Web题 0x00 题目描述 这是偶尔遇到的某网安交流群的入群题,题目没有任何的提示,直接给了一个txt文件. 0x01 解题过程 通过给的这个文 ...