Turn the corner
Problem Description
Mr. West bought a new car! So he is travelling around the city.<br><br>One day he comes to a vertical corner. The street he is currently in has a width x, the street he wants to turn to has a width y. The car has a length l and a width d.<br><br>Can Mr. West go across the corner?<br><img src=../../../data/images/2438-1.jpg><br>
Input
Every line has four real numbers, x, y, l and w.<br>Proceed to the end of file.<br>
Output
If he can go across the corner, print "yes". Print "no" otherwise.<br>
Sample Input
10 6 13.5 4<br>10 6 14.5 4<br>
Sample Output
yes<br>no<br>
Source
2008 Asia Harbin Regional Contest Online
題意：車轉角問題，讓他能拐過彎道
思路：其實主要是數學問題算公式
感想：相比搜索，二分真是好做多了
AC代碼：
#include <cstdio>
#include<iostream>
#include<stdio.h>
#include<vector>
#include<algorithm>
#include<numeric>
#include<math.h>
#include<string.h>
#include<map>
#include<set>
#include<vector>
#include<iomanip>
using namespace std;
double PI=acos(-1.0);
double x,y,v,w;
double s (double a)
{
return v*cos(a)+(w-x*cos(a))/sin(a);
}
int main()
{
double r,l,mid,midd;
while(cin>>x>>y>>v>>w)
{
l=0;r=PI/2;
while(r-l>0.0000001)
{
mid=(r+2*l)/3;
midd=(l+r*2)/3;
if(s(mid)>s(midd))
r=midd;
else
l=mid;
}
if(s(l)>y) cout<<"no"<<endl;
else cout<<"yes"<<endl;
}
return 0;
}