Codeforces Round 381 (Div. 1)
E
Gosha is hunting
Codeforces
3000
原题
← D→
翻译中…

Gosha is hunting. His goal is to catch as many Pokemons as possible. Gosha has $*a*$ Poke Balls and $*b*$ Ultra Balls. There are $*n*$ Pokemons. They are numbered $1$ through $*n*$. Gosha knows that if he throws a Poke Ball at the $*i*$-th Pokemon he catches it with probability $*p*_{*i*}$. If he throws an Ultra Ball at the $*i*$-th Pokemon he catches it with probability $*u*_{*i*}$. He can throw at most one Ball of each type at any Pokemon.

翻译中…

The hunting proceeds as follows: at first, Gosha chooses no more than $*a*$ Pokemons at which he will throw Poke Balls and no more than $*b*$ Pokemons at which he will throw Ultra Balls. After that, he throws the chosen Balls at the chosen Pokemons. If he throws both Ultra Ball and Poke Ball at some Pokemon, he is caught if and only if he is caught by any of these Balls. The outcome of a throw doesn't depend on the other throws.

翻译中…

Gosha would like to know what is the expected number of the Pokemons he catches if he acts in an optimal way. In other words, he would like to know the maximum possible expected number of Pokemons can catch.

翻译中…

Input

翻译中…

The first line contains three integers $*n*$, $*a*$ and $*b*$ ($2 ≤ *n* ≤ 2000$, $0 ≤ *a*, *b* ≤ *n*$) — the number of Pokemons, the number of Poke Balls and the number of Ultra Balls.

翻译中…

The second line contains $*n*$ real values $*p*_{1}, *p*_{2}, ..., *p*_{*n*}$ ($0 ≤ *p*_{*i*} ≤ 1$), where $*p*_{*i*}$ is the probability of catching the $*i*$-th Pokemon if Gosha throws a Poke Ball to it.

翻译中…

The third line contains $*n*$ real values $*u*_{1}, *u*_{2}, ..., *u*_{*n*}$ ($0 ≤ *u*_{*i*} ≤ 1$), where $*u*_{*i*}$ is the probability of catching the $*i*$-th Pokemon if Gosha throws an Ultra Ball to it.

翻译中…

All the probabilities are given with exactly three digits after the decimal separator.

翻译中…

Output

翻译中…

Print the maximum possible expected number of Pokemons Gosha can catch. The answer is considered correct if it's absolute or relative error doesn't exceed $10^{ - 4}$.

翻译中…

样例

Input #1
3 2 2
1.000 0.000 0.500
0.000 1.000 0.500
Output #1
2.75
InputCopy OutputCopy
Input #2
4 1 3
0.100 0.500 0.500 0.600
0.100 0.500 0.900 0.400
Output #2
2.16
InputCopy OutputCopy
Input #3
3 2 0
0.412 0.198 0.599
0.612 0.987 0.443
Output #3
1.011
InputCopy OutputCopy
题目信息
题号
739E
时间限制
5 s
内存限制
256 MB
标签
暴力
数据结构
动态规划
网络流
数学
概率论
排序

题面与样例版权归 Codeforces 及出题人所有;中文翻译由 AI 生成(CI 管线),如有出入请以原文为准。