POJ.1379.Run Away(模拟退火)
Posted SovietPower
tags:
篇首语:本文由小常识网(cha138.com)小编为大家整理,主要介绍了POJ.1379.Run Away(模拟退火)相关的知识,希望对你有一定的参考价值。
POJ输出不能用%lf!
mmp从4.30改到6.00,把4.30交的一改也过了。
于是就有了两份。。
//392K 500MS
//用两点构成的矩形更新,就不需要管边界了
#include <cmath>
#include <cstdio>
#include <cctype>
#include <algorithm>
#define gc() getchar()
#define Rate (0.9)
#define Rand() (1.0*((rand()<<1)-RAND_MAX)/RAND_MAX)
const int N=1005;
int n,X,Y;
double DIS,ans_dis[20];
struct Node{
double x,y;
Node() {}
Node(double x,double y):x(x),y(y) {}
}p[N],ans[30];
inline int read()
{
int now=0;register char c=gc();
for(;!isdigit(c);c=gc());
for(;isdigit(c);now=now*10+c-'0',c=gc());
return now;
}
inline double Sqr(double x){
return x*x;
}
inline double Dis(double x,double y,int i){
return sqrt(Sqr(x-p[i].x)+Sqr(y-p[i].y));
}
double Calc(double x,double y)
{
double res=DIS;
for(int i=1; i<=n; ++i)
res=std::min(res,Dis(x,y,i));
return res;
}
void Print(){
for(int i=1; i<=15; ++i) printf("%d:%.5lf %.5lf %.5lf %d %d\n",i,ans[i].x,ans[i].y,ans_dis[i],X,Y);
}
void Solve()
{
DIS=sqrt(X*X+Y*Y);
const int tot=15;
for(int i=1; i<=tot; ++i)
ans[i].x=1.0*rand()/RAND_MAX*X,ans[i].y=1.0*rand()/RAND_MAX*Y,ans_dis[i]=Calc(ans[i].x,ans[i].y);
double T=DIS,xx,yy,dis;//this...
while(T>0.01)
{1
for(int i=1; i<=tot; ++i)
for(int j=1; j<=30; ++j)
{
xx=ans[i].x+T*Rand(), yy=ans[i].y+T*Rand();
if(xx<0||xx>X||yy<0||yy>Y) continue;//!
dis=Calc(xx,yy);
if(dis>ans_dis[i]) ans[i]=Node(xx,yy),ans_dis[i]=dis;
}
T*=Rate;
}
int res=1;
for(int i=2; i<=tot; ++i)
if(ans_dis[i]>ans_dis[res]) res=i;
printf("The safest point is (%.1f, %.1f).\n",ans[res].x,ans[res].y);
}
int main()
{
srand(20180428);
int T=read();
while(T--)
{
X=read(),Y=read(),n=read();
for(int i=1; i<=n; ++i) p[i].x=read(),p[i].y=read();
Solve();
}
return 0;
}
另一种写法:
//392K 1188MS
#include <cmath>
#include <cstdio>
#include <cctype>
#include <algorithm>
#define gc() getchar()
#define Rate (0.97)
//#define Rand() (1.0*((rand()<<1)-RAND_MAX)/RAND_MAX)
#define Rand() (1.0*rand()/RAND_MAX)
const int N=1005;
int n,X,Y;
double DIS,ans_dis[30];
struct Node{
double x,y;
Node() {}
Node(double x,double y):x(x),y(y) {}
}p[N],ans[30];
inline int read()
{
int now=0;register char c=gc();
for(;!isdigit(c);c=gc());
for(;isdigit(c);now=now*10+c-'0',c=gc());
return now;
}
inline double Sqr(double x){
return x*x;
}
inline double Dis(double x,double y,int i){
return sqrt(Sqr(x-p[i].x)+Sqr(y-p[i].y));
}
double Calc(double x,double y)
{
double res=1e9;//DIS;
for(int i=1; i<=n; ++i)
res=std::min(res,Dis(x,y,i));
return res;
}
void Rand_Point(double &x,double &y,Node a,Node b){
x=a.x+(b.x-a.x)*Rand(), y=a.y+(b.y-a.y)*Rand();
}
void Solve()
{
DIS=sqrt(X*X+Y*Y);
const int tot=15;
ans[1]=Node(0,0), ans[2]=Node(X,Y), ans[3]=Node(X,0), ans[4]=Node(0,Y);//
for(int i=5; i<=tot; ++i)
Rand_Point(ans[i].x,ans[i].y,ans[1],ans[2]);
// ans[i].x=Rand()*X,ans[i].y=Rand()*Y;
for(int i=1; i<=tot; ++i) ans_dis[i]=Calc(ans[i].x,ans[i].y);
double T=std::min(X,Y),xx,yy,dis;//this...
while(T>0.01)
{
for(int i=1; i<=tot; ++i)
for(int j=1; j<=20; ++j)
{
Rand_Point(xx,yy,Node(std::max(0.0,ans[i].x-T),std::max(0.0,ans[i].y-T)),Node(std::min(1.0*X,ans[i].x+T),std::min(1.0*Y,ans[i].y+T)));
dis=Calc(xx,yy);
if(dis>ans_dis[i]) ans[i]=Node(xx,yy),ans_dis[i]=dis;
}
T*=Rate;
}
int res=1;
for(int i=2; i<=tot; ++i)
if(ans_dis[i]>ans_dis[res]) res=i;
printf("The safest point is (%.1f, %.1f).\n",ans[res].x,ans[res].y);
}
int main()
{
#ifndef ONLINE_JUDGE
freopen("1.in","r",stdin);
// freopen("1.out","w",stdout);
#endif
srand(20180428);
int T=read();
while(T--)
{
X=read(),Y=read(),n=read();
for(int i=1; i<=n; ++i) p[i].x=read(),p[i].y=read();
Solve();
}
return 0;
}
以上是关于POJ.1379.Run Away(模拟退火)的主要内容,如果未能解决你的问题,请参考以下文章