2016 计蒜之道 初赛 第二场(待补)

A. 联想公司的 logo 设计

#include<bits/stdc++.h>
using namespace std;
#define For(i,n) for(int i=1;i<=n;i++)
#define Fork(i,k,n) for(int i=k;i<=n;i++)
#define Rep(i,n) for(int i=0;i<n;i++)
#define ForD(i,n) for(int i=n;i;i--)
#define ForkD(i,k,n) for(int i=n;i>=k;i--)
#define RepD(i,n) for(int i=n;i>=0;i--)
#define Forp(x) for(int p=Pre[x];p;p=Next[p])
#define Forpiter(x) for(int &p=iter[x];p;p=Next[p])  
#define Lson (o<<1)
#define Rson ((o<<1)+1)
#define MEM(a) memset(a,0,sizeof(a));
#define MEMI(a) memset(a,127,sizeof(a));
#define MEMi(a) memset(a,128,sizeof(a));
#define INF (2139062143)
#define F (100000007)
#define pb push_back
#define mp make_pair 
#define fi first
#define se second
#define vi vector<int> 
#define pi pair<int,int>
#define SI(a) ((a).size())
typedef long long ll;
typedef unsigned long long ull;
ll mul(ll a,ll b){return (a*b)%F;}
ll add(ll a,ll b){return (a+b)%F;}
ll sub(ll a,ll b){return (a-b+llabs(a-b)/F*F+F)%F;}
void upd(ll &a,ll b){a=(a%F+b%F)%F;}
int read()
{
    int x=0,f=1; char ch=getchar();
    while(!isdigit(ch)) {if (ch=='-') f=-1; ch=getchar();}
    while(isdigit(ch)) { x=x*10+ch-'0'; ch=getchar();}
    return x*f;
} const double PI = 3.141592653589793238462643383249901429;  

struct Round {  
    double x, y;  
    double r;  
} r[2];  

double sqr(double x) {return x*x;}
int main()
{
//  freopen("A.in","r",stdin);
//  freopen(".out","w",stdout);

    double l1,l2,xita;
    cin>>l1>>l2>>xita;

    xita=xita*PI/180;

    r[0].x=l1/2;
    r[0].y=0;
    r[0].r=l1/2;
    r[1].x=cos(xita)*l2/2;
    r[1].y=sin(xita)*l2/2;
    r[1].r=l2/2;

    double ans=sqrt(sqr(r[0].r)+sqr(r[1].r)-2*r[0].r*r[1].r*cos(xita));
    ans+=l1/2+l2/2;

    ans=sqr(ans/2)*PI;

    printf("%.10lf\n",ans);

    return 0;
}

B.联想的显示屏校准

同CERC 2006,Highway 但是n变大了，
要用数学方法
//待填