zoukankan      html  css  js  c++  java
  • B

    Problem description

    SmallR is an archer. SmallR is taking a match of archer with Zanoes. They try to shoot in the target in turns, and SmallR shoots first. The probability of shooting the target each time is  for SmallR while  for Zanoes. The one who shoots in the target first should be the winner.

    Output the probability that SmallR will win the match.

    Input

    A single line contains four integers .

    Output

    Print a single real number, the probability that SmallR will win the match.

    The answer will be considered correct if the absolute or relative error doesn't exceed 10 - 6.

    Examples

    Input

    1 2 1 2

    Output

    0.666666666667
    解题思路:等比数列极限求和。推导公式如下:

    AC代码:
    1 #include <bits/stdc++.h>
    2 using namespace std;
    3 int main(){
    4     double a,b,c,d;
    5     cin>>a>>b>>c>>d;
    6     cout<<setiosflags(ios::fixed)<<setprecision(12)<<((a/b)*(1/(1-(1-a/b)*(1-c/d))))<<endl;
    7     //printf("%.12f
    ",(a/b)*(1/(1-(1-a/b)*(1-c/d))));
    8     return 0;
    9 }
  • 相关阅读:
    JDBCUtils
    C3P0配置
    反射基本常识(二)
    反射基本常识(一)
    String to Integer (atoi)
    ZigZag Conversion
    Longest Palindromic Substring
    Palindrome Number
    Reverse Integer
    Longest Substring Without Repeating Characters
  • 原文地址:https://www.cnblogs.com/acgoto/p/9157300.html
Copyright © 2011-2022 走看看