Gotta Go Fast

CodeForces - 865C

You're trying to set the record on your favorite video game. The game consists of Nlevels, which must be completed sequentially in order to beat the game. You usually complete each level as fast as possible, but sometimes finish a level slower. Specifically, you will complete the i-th level in either Fi seconds or Si seconds, where Fi < Si, and there's a Pi percent chance of completing it in Fi seconds. After completing a level, you may decide to either continue the game and play the next level, or reset the game and start again from the first level. Both the decision and the action are instant.

Your goal is to complete all the levels sequentially in at most R total seconds. You want to minimize the expected amount of time playing before achieving that goal. If you continue and reset optimally, how much total time can you expect to spend playing?

Input

The first line of input contains integers N and R , the number of levels and number of seconds you want to complete the game in, respectively. N lines follow. The ith such line contains integers Fi, Si, Pi (1 ≤ Fi < Si ≤ 100, 80 ≤ Pi ≤ 99), the fast time for level i, the slow time for level i, and the probability (as a percentage) of completing level i with the fast time.

Output

Print the total expected time. Your answer must be correct within an absolute or relative error of 10 - 9.

Formally, let your answer be a, and the jury's answer be b. Your answer will be considered correct, if .

Examples

Input
1 8
2 8 81
Output
3.14
Input
2 30
20 30 80
3 9 85
Output
31.4
Input
4 319
63 79 89
79 97 91
75 87 88
75 90 83
Output
314.159265358

Note

In the first example, you never need to reset. There's an 81% chance of completing the level in 2 seconds and a 19% chance of needing 8 seconds, both of which are within the goal time. The expected time is 0.81·2 + 0.19·8 = 3.14.

In the second example, you should reset after the first level if you complete it slowly. On average it will take 0.25 slow attempts before your first fast attempt. Then it doesn't matter whether you complete the second level fast or slow. The expected time is 0.25·30 + 20 + 0.85·3 + 0.15·9 = 31.4.

sol:

dp[i][j]表示当前为第i关,已用时j,从当前开始通关的用时期望
tmp表示从头开始通关的用时期望
设当前状态为(i,j):
①如果在挑战第i关前选择重新开始游戏,则通关的期望值tmp
②如果通过第i关用时为a[i],则继续进行游戏并通关的期望值为(dp[i+1][j+a[i]]+a[i])*p[i]
③如果通过第i关用时为b[i],则继续进行游戏并通关的期望值为(dp[i+1][j+b[i]]+b[i])*(1-p[i])

/*
dp[i][j]表示当前为第i关,已用时j,从当前开始通关的用时期望
tmp表示从头开始通关的用时期望
设当前状态为(i,j):
①如果在挑战第i关前选择重新开始游戏,则通关的期望值tmp
②如果通过第i关用时为a[i],则继续进行游戏并通关的期望值为(dp[i+1][j+a[i]]+a[i])*p[i]
③如果通过第i关用时为b[i],则继续进行游戏并通关的期望值为(dp[i+1][j+b[i]]+b[i])*(1-p[i])
*/
#include <bits/stdc++.h>
using namespace std;
typedef int ll;
inline ll read()
{
ll s=; bool f=; char ch=' ';
while(!isdigit(ch)) {f|=(ch=='-'); ch=getchar();}
while(isdigit(ch)) {s=(s<<)+(s<<)+(ch^); ch=getchar();}
return (f)?(-s):(s);
}
#define R(x) x=read()
inline void write(ll x)
{
if(x<) {putchar('-'); x=-x;}
if(x<) {putchar(x+''); return;}
write(x/); putchar((x%)+'');
}
#define W(x) write(x),putchar(' ')
#define Wl(x) write(x),putchar('\n')
const int N=,M=;
const double eps=1e-;
int n,m,a[N],b[N],p[N];
double dp[N][M];
inline bool chk(double tmp)
{
int i,j;
for(i=n;i>=;i--)
{
for(j=m+;j<M;j++) dp[i+][j]=tmp; //重来
for(j=;j<=m;j++)
{
double t1=(double)(dp[i+][j+a[i]]+a[i])*p[i]/;
double t2=(double)(dp[i+][j+b[i]]+b[i])*(-p[i])/;
dp[i][j]=min(t1+t2,tmp);
}
}
return dp[][]<tmp;
}
int main()
{
freopen("data.in","r",stdin);
int i;
R(n); R(m);
for(i=;i<=n;i++)
{
R(a[i]); R(b[i]); R(p[i]);
}
double l=0.00,r=1e10,mid;
for(i=;i<=;i++)
{
mid=(l+r)*0.50;
if(chk(mid)) r=mid;
else l=mid;
}
printf("%.12lf\n",l);
return ;
}
/*
input
4 319
63 79 89
79 97 91
75 87 88
75 90 83
output
314.159265358
*/

codeforces865C的更多相关文章

  1. #3 Codeforces-865C Gotta Go Fast(期望dp)

    题意:一个游戏一共有n个关卡,对于第i关,用a[i]时间通过的概率为p[i],用b[i]通过的时间为1-p[i],每通过一关后可以选择继续下一关或者时间清0并从第一关开始,先要求通过所有关卡的时间和不 ...

随机推荐

  1. 编写函数实现strcmp( )函数功能

    strcmp(字符串1,字符串2) 作用是比较字符串1和字符串2.两个字符串从左至右逐个字符比较(按照字符的ASCII码值的大小)(即减法比较),直到字符不同或者遇见’\0’为止 如果全部字符都相同, ...

  2. 【leetcode】287. 寻找重复数

    题目链接:传送门 题目描述: 给定一个数组 nums 包含 n + 1 个整数,每个整数在 1 到 n 之间,包括 1 和 n.现在假设数组中存在一个重复的数字,找到该重复的数字. 注意 不能修改数组 ...

  3. java7:核心技术与最佳实践读书笔记——对象生命周期

    流程:字节码文件(.class) -> 类加载 -> 类链接 -> 类初始化 -> 对象初始化 -> 对象创建 -> 对象使用 -> 对象回收 . 1.Jav ...

  4. sql 行数据找出最大的及所有数据最大的

    SELECT @charges=ISNULL(MAX(a.maxcharge), 0.00) FROM( SELECT (SELECT MAX(maxcharge) FROM(VALUES(ilong ...

  5. C#UDP异步通信

    using SetingDemo.LogHelp;using SetingDemo.SingleRowDeclare;using System;using System.Collections.Gen ...

  6. Signalr Vue Echarts绘制实时CPU使用率

    后端基于Asp.net webapi,前端Vue,前后端分离,该demo仅做演示,实现的细节可以自己优化 Echarts:4.2.1  可参考 官网 Jquery:3.4.1 Signalr:2.4. ...

  7. div可以同时设置背景图片和背景颜色吗?

    前言 当然可以同时设置 当图片背景色不透明时 情况一:当图片的长.宽 >= div的长.宽时 我们最终看到div背景是图片,之所以说是最终看到,是因为在页面加载时,我们先看到的div背景是颜色, ...

  8. java中long类型转换为int类型

    由int类型转换为long类型是向上转换,可以直接进行隐式转换,但由long类型转换为int类型是向下转换,可能会出现数据溢出情况: 主要以下几种转换方法,供参考: 一.强制类型转换 [java] l ...

  9. XWork配置示例

    <?xml version="1.0" encoding="UTF-8"?><!DOCTYPE validators PUBLIC       ...

  10. vim技巧总结

    自动补齐CTRL+N/CTRL+P vim 自动补全 颜色设置 hi Pmenu ctermfg=black ctermbg=gray guibg=#444444 hi PmenuSel ctermf ...