Codeforces Round #289 (Div. 2, ACM ICPC Rules) E. Pretty Song 算贡献+前缀和
1 second
256 megabytes
standard input
standard output
When Sasha was studying in the seventh grade, he started listening to music a lot. In order to evaluate which songs he likes more, he introduced the notion of the song's prettiness. The title of the song is a word consisting of uppercase Latin letters. The prettiness of the song is the prettiness of its title.
Let's define the simple prettiness of a word as the ratio of the number of vowels in the word to the number of all letters in the word.
Let's define the prettiness of a word as the sum of simple prettiness of all the substrings of the word.
More formally, let's define the function vowel(c) which is equal to 1, if c is a vowel, and to 0 otherwise. Let si be the i-th character of string s, and si..j be the substring of word s, staring at the i-th character and ending at the j-th character (sisi + 1... sj, i ≤ j).
Then the simple prettiness of s is defined by the formula:

The prettiness of s equals

Find the prettiness of the given song title.
We assume that the vowels are I, E, A, O, U, Y.
The input contains a single string s (1 ≤ |s| ≤ 5·105) — the title of the song.
Print the prettiness of the song with the absolute or relative error of at most 10 - 6.
IEAIAIO
28.0000000
BYOB
5.8333333
YISVOWEL
17.0500000
In the first sample all letters are vowels. The simple prettiness of each substring is 1. The word of length 7 has 28 substrings. So, the prettiness of the song equals to 28.
题目链接:http://codeforces.com/contest/509/problem/E
题意:给你一个字符串,求字串中I, E, A, O, U, Y.的比例和;
例如:BYOB
B 0 BY 1/2 BYO 2/3 BYOB 1/2
Y 1 YO 1 YOB 2/3
O 1 OB 1/2
B 0
0+1+1/2+2/3+1/2+1+1+2/3+1+1/2+0=5.833333
思路:显然算贡献的题;
对于一个字符,左边有l个,右边有r个,包含其的字串总有(l+1)*(r+1)个;
其贡献会形成一个平行四边行
1 1/2 1/3 1/4
1/2 1/3 1/4 1/5
用前缀和预处理即可;
#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<iostream>
#include<cstdio>
#include<cmath>
#include<string>
#include<queue>
#include<algorithm>
#include<stack>
#include<cstring>
#include<vector>
#include<list>
#include<set>
#include<map>
using namespace std;
#define ll long long
#define pi (4*atan(1.0))
#define mk make_pair
#define eps 1e-7
#define bug(x) cout<<"bug"<<x<<endl;
const int N=5e5+,M=1e6+,inf=;
const ll INF=1e18+,mod=; /// 数组大小
char ch[]={'I','E','A','O','U','Y'},s[N];
double sum1[N],sum2[N],sum3[N];
int check(char a)
{
for(int i=;i<;i++)
if(a==ch[i])return ;
return ;
}
int main()
{
scanf("%s",s+);
int n=strlen(s+);
for(int i=;i<=n;i++)
sum1[i]=sum1[i-]+(1.0*/i);
for(int i=;i<=n;i++)
sum2[i]=sum2[i-]+sum1[i];
for(int i=n,j=;i>=;i--,j++)
sum3[j]=sum3[j-]+sum1[n]-sum1[i-];
double ans=0.0;
for(int i=;i<=n;i++)
{
if(check(s[i]))
{
int l=i;
int r=n-i+;
ans+=1.0*sum1[n]*l;
ans-=sum2[l-];
ans-=sum3[l-];
}
//cout<<ans<<endl;
}
printf("%f\n",ans);
return ;
}
1 second
256 megabytes
standard input
standard output
When Sasha was studying in the seventh grade, he started listening to music a lot. In order to evaluate which songs he likes more, he introduced the notion of the song's prettiness. The title of the song is a word consisting of uppercase Latin letters. The prettiness of the song is the prettiness of its title.
Let's define the simple prettiness of a word as the ratio of the number of vowels in the word to the number of all letters in the word.
Let's define the prettiness of a word as the sum of simple prettiness of all the substrings of the word.
More formally, let's define the function vowel(c) which is equal to 1, if c is a vowel, and to 0 otherwise. Let si be the i-th character of string s, and si..j be the substring of word s, staring at the i-th character and ending at the j-th character (sisi + 1... sj, i ≤ j).
Then the simple prettiness of s is defined by the formula:

The prettiness of s equals

Find the prettiness of the given song title.
We assume that the vowels are I, E, A, O, U, Y.
The input contains a single string s (1 ≤ |s| ≤ 5·105) — the title of the song.
Print the prettiness of the song with the absolute or relative error of at most 10 - 6.
IEAIAIO
28.0000000
BYOB
5.8333333
YISVOWEL
17.0500000
In the first sample all letters are vowels. The simple prettiness of each substring is 1. The word of length 7 has 28 substrings. So, the prettiness of the song equals to 28.
Codeforces Round #289 (Div. 2, ACM ICPC Rules) E. Pretty Song 算贡献+前缀和的更多相关文章
- codeforces水题100道 第十八题 Codeforces Round #289 (Div. 2, ACM ICPC Rules) A. Maximum in Table (brute force)
题目链接:http://www.codeforces.com/problemset/problem/509/A题意:f[i][1]=f[1][i]=1,f[i][j]=f[i-1][j]+f[i][j ...
- Codeforces Round #289 (Div. 2, ACM ICPC Rules) A. Maximum in Table【递推】
A. Maximum in Table time limit per test 2 seconds memory limit per test 256 megabytes input standard ...
- 贪心 Codeforces Round #289 (Div. 2, ACM ICPC Rules) B. Painting Pebbles
题目传送门 /* 题意:有 n 个piles,第 i 个 piles有 ai 个pebbles,用 k 种颜色去填充所有存在的pebbles, 使得任意两个piles,用颜色c填充的pebbles数量 ...
- 递推水题 Codeforces Round #289 (Div. 2, ACM ICPC Rules) A. Maximum in Table
题目传送门 /* 模拟递推水题 */ #include <cstdio> #include <iostream> #include <cmath> #include ...
- Codeforces Round #622 (Div. 2) B. Different Rules(数学)
Codeforces Round #622 (Div. 2) B. Different Rules 题意: 你在参加一个比赛,最终按两场分赛的排名之和排名,每场分赛中不存在名次并列,给出参赛人数 n ...
- Codeforces Round #289 Div 2
A. Maximum in Table 题意:给定一个表格,它的第一行全为1,第一列全为1,另外的数满足a[i][j]=a[i-1][j]+a[i][j-1],求这个表格中的最大的数 a[n][n]即 ...
- Codeforces Round #554 (Div. 2) F2. Neko Rules the Catniverse (Large Version) (矩阵快速幂 状压DP)
题意 有nnn个点,每个点只能走到编号在[1,min(n+m,1)][1,min(n+m,1)][1,min(n+m,1)]范围内的点.求路径长度恰好为kkk的简单路径(一个点最多走一次)数. 1≤n ...
- Codeforces Round #381 (Div. 1) B. Alyona and a tree dfs序 二分 前缀和
B. Alyona and a tree 题目连接: http://codeforces.com/contest/739/problem/B Description Alyona has a tree ...
- Codeforces Round #294 (Div. 2) D. A and B and Interesting Substrings [dp 前缀和 ]
传送门 D. A and B and Interesting Substrings time limit per test 2 seconds memory limit per test 256 me ...
随机推荐
- Comparable和Comparator的使用
1:对象实现Comparable, 那么对象就具有了比较功能 package comparableAndComparator; import java.util.Collections; import ...
- mybatis中使用where in查询时的注意事项
我使用的时候collection值为mapper的参数名如:int deleteRoleByUserIds(@Param("userIds") String[] userIds); ...
- spark shuffle原理
1.spark中窄依赖的时候不需要shuffle,只有宽依赖的时候需要shuffle,mapreduce中map到reduce必须经过shuffle 2.spark中的shuffle fetch的时候 ...
- iOS开发--沙盒
IOS中的沙盒机制(SandBox)是一种安全体系,它规定了应用程序只能在为该应用创建的文件夹内读取文件,不可以访问其他地方的内容.所有的非代码文件都保存在这个地方,比如图片.声音.属性列表和文本文件 ...
- 渗透msf工具中andorid被控端的实现
msf中andoird端的实现代码一共只有8k 核心代码就是下载者. 下载dex,动态执行dex.
- C# 后台动态添加标签(span,div) 以及模板添加
很多时候.我们需要在后台用C#代码添加html标签.而不是在html源码中添加. 比如在html源码中简单的一个input 标签 <input type="type" nam ...
- css样式属性-字体和隐藏
1.字体 font-family:字体: <body> <div style="font-family:宋体">宋体</div> </bo ...
- OAuth 白话简明教程 1.简述
转自:http://www.cftea.com/c/2016/11/6702.asp OAuth 白话简明教程 1.简述 OAuth 白话简明教程 2.授权码模式(Authorization Code ...
- quartz开源作业调度框架的配置
quartz开源作业调度框架的job服务实现,Quartz是一个完全由java编写的开源作业调度框架,使用时候需要创建一个实现org.quartz.Job接口的java类,Job接口包含唯一的方法: ...
- linux下删除大量文件提示参数过长解决办法
linux下删除大量文件提示参数过长解决办法:在当前目录下rm -rf * 在linux中删除大量文件时,直接用rm会出现:-bash: /bin/rm: 参数列表过长的错误. 这时可以用find命令 ...