bzoj1857 [SCOI2010]传送带
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 }
