[Gym - 102861A] A - Sticker Album 概率dp-白红宇

[Gym - 102861A] A - Sticker Album 概率dp

阅读量：341 次

发布时间：2019-03-04

本文共 1148 字，大约阅读时间需要 3 分钟。

???????????????????????????????dp[i]???dp[i]?????i?????????n???????????????????i=n?????i=0???dp[0]???

?????

?a=0??????k????k?0?b?????1/(b+1)??????[dp[i] = \frac{\sum_{k=1}^{b} (dp[i + k] + 1)}{b} + 1]???sum?dp[i+1]?dp[i+b]???

?a?0??????k????k?a?b?????1/(b-a+1)??????[dp[i] = \frac{\sum_{k=a}^{b} (dp[i + k] + 1)}{b - a + 1}]???sum?dp[i+a]?dp[i+b]???

????

double dp[maxn];int main() {    int n, a, b;    cin >> n >> a >> b;    int len = b - a + 1;    dp[n] = 0.0;    double sum = 0.0;    for (int i = n - 1; i >= 0; --i) {        if (!a) {            dp[i] = (sum + len) / (len - 1.0);            sum -= dp[i + b];            sum += dp[i];        } else {            dp[i] = sum / len + 1;            sum -= dp[i + b];            sum += dp[i + a - 1];        }    }    printf("%.8lf", dp[0]);}

????

???????????maxn??????dp??????????dp[n]????0.0??????n?????????

??????i=n-1???????i=0????????????dp[n]????????????

??a=0?????a?0????k????????0?b??????????????????sum???sum?dp[i+1]?dp[i+b]???

??a?0?????a??0?????????a?b??????????????????sum???sum?dp[i+a]?dp[i+b]???

???????dp[0]??????0?????????

???????????????????????????????????????????????????????????

转载地址：http://khmh.baihongyu.com/

你可能感兴趣的文章

pip install goose-extractor // SyntaxError: Missing parentheses in call to 'print'

pip install mysqlclient报错

pip install 出现报asciii码错误的解决

pip throws TypeError: parse() got an unexpected keyword argument ‘transport_encoding‘ 在尝试安装新软件包时

pip 升级报错AttributeError: ‘NoneType’ object has no attribute ‘bytes’

pip 安装opencv-python卡死

pip 安装出现异常

Pip 安装失败:需要 SSL

Pip 安装挂起

pip 或 pip3 为 Python 3 安装包?

pip 文件损坏导致 pip无法使用报错 ImportError: cannot import name 'main' from 'pip._int

pip 无法从 requirements.txt 安装软件包

pip/pip3更换国内源

pip3 install PyQt5 --user 失败

pip3命令全解析：Python3包管理工具的详细使用指南

pip3安装命令重复创建文件‘/tmp/pip-install-xxxxx/package‘失败

PIPE 接口信号列表

pipeline配置与管理Job企业级实战

pipeline项目配置实战