bzoj1857 [SCOI2010]传送带

Posted 2020-06-14

题目链接

简单的三分套三分，精度要求也不高，随便玩。。。

 1 #include<algorithm>
 2 #include<iostream>
 3 #include<cstdlib>
 4 #include<cstring>
 5 #include<cstdio>
 6 #include<string>
 7 #include<cmath>
 8 #include<ctime>
 9 #include<queue>
10 #include<stack>
11 #include<map>
12 #include<set>
13 #define rre(i,r,l) for(int i=(r);i>=(l);i--)
14 #define re(i,l,r) for(int i=(l);i<=(r);i++)
15 #define Clear(a,b) memset(a,b,sizeof(a))
16 #define inout(x) printf("%d",(x))
17 #define douin(x) scanf("%lf",&x)
18 #define strin(x) scanf("%s",(x))
19 #define LLin(x) scanf("%lld",&x)
20 #define op operator
21 #define CSC main
22 typedef unsigned long long ULL;
23 typedef const int cint;
24 typedef long long LL;
25 using namespace std;
26 void inin(int &ret)
27 {
28     ret=0;int f=0;char ch=getchar();
29     while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=1;ch=getchar();}
30     while(ch>=‘0‘&&ch<=‘9‘)ret*=10,ret+=ch-‘0‘,ch=getchar();
31     ret=f?-ret:ret;
32 }
33 const double eps=1e-8;
34 double f(double x){return x*x;}
35 struct xl
36 {
37     double x,y;
38     xl(double x=0,double y=0):x(x),y(y){}
39     void in(){douin(x),douin(y);}
40     xl op - (const xl &rhs){return xl(x-rhs.x,y-rhs.y);}
41     xl op + (const xl &rhs){return xl(x+rhs.x,y+rhs.y);}
42     xl op * (const double &rhs){return xl(x*rhs,y*rhs);}
43     xl op / (const double &rhs){return xl(x/rhs,y/rhs);}
44 };
45 double dis(const xl &a,const xl &b){return sqrt(f(a.x-b.x)+f(a.y-b.y));}
46 xl A,B,C,D;
47 double v1,v2,u;
48 double getans(xl x)
49 {
50     xl l=C,r=D;
51     while(dis(l,r)>1e-5)
52     {
53         xl v=r-l;
54         xl V1=v/3.0,V2=v-V1;
55         xl ll=l+V1,rr=l+V2;
56         double ret1=dis(x,A)/v1+dis(ll,D)/v2+dis(ll,x)/u;
57         double ret2=dis(x,A)/v1+dis(rr,D)/v2+dis(rr,x)/u;
58         if(ret1<ret2)r=rr;
59         else l=ll;
60     }
61     return dis(x,A)/v1+dis(l,D)/v2+dis(l,x)/u;
62 }
63 int CSC()
64 {
65     A.in(),B.in(),C.in(),D.in();
66     douin(v1),douin(v2),douin(u);
67     xl l=A,r=B;
68     while(dis(l,r)>1e-5)
69     {
70         xl v=r-l;
71         xl V1=v/3.0,V2=v-V1;
72         xl ll=l+V1,rr=l+V2;
73         if(getans(ll)<getans(rr))r=rr;
74         else l=ll;
75     }
76     printf("%.2f",getans(l));
77     return 0;
78 }