标签：des blog io ar os sp java for strong
| Time Limit: 3000MS | Memory Limit: 65536K | |
| Total Submissions: 6482 | Accepted: 1993 |
Description
Input
Output
Sample Input
3 1000 50 1 10 10 100 100 4 10 10 10 90 90 10 90 90 3000 3000 4 1200 85 63 2500 2700 2650 2990 100
Sample Output
The safest point is (1000.0, 50.0). The safest point is (50.0, 50.0). The safest point is (1433.0, 1669.8).
思路:直接按照题解做的,首先列举30个随机点,然后分别进行短距离的随机尝试
#include <cstdio>
#include <ctime>
#include <cstring>
#include <cmath>
#include <cstdlib>
#include <algorithm>
using namespace std;
const double Pi=acos(-1.0);
const double eps=1e-3;
const double inf=1e20;
double px[31],py[31],d[31],x[1111],y[1111];
double caldis(double x1,double y1,double x2,double y2){
return sqrt((x1-x2)*(x1-x2)+(y1-y2)*(y1-y2));
}
int main(){
int T;
scanf("%d",&T);
srand(9876543);
while(T--){
int a,b,m;
scanf("%d%d%d",&a,&b,&m);
for(int i=0;i<m;i++){
scanf("%lf%lf",x+i,y+i);
}
for(int i=0;i<30;i++){
px[i]=(double)(rand()%1000+1)/1000.000*a;
py[i]=(double)(rand()%1000+1)/1000.000*b;
d[i]=inf;
for(int j=0;j<m;j++)d[i]=min(d[i],caldis(px[i],py[i],x[j],y[j]));
}
double delta=double(max(a,b))/(sqrt(1.0*m));
while(delta>eps){
for(int i=0;i<30;i++){
double tx=px[i],ty=py[i];
for(int j=0;j<30;j++){
double theta=(double)(rand()%1000+1)/1000.000*10*Pi;
double dx=delta*cos(theta);
double dy=delta*sin(theta);
tx+=dx;ty+=dy;
if(tx<0||tx>a||ty<0||ty>b){tx-=dx;ty-=dy;continue;}
double td=inf;
for(int k=0;k<m;k++)td=min(td,caldis(tx,ty,x[k],y[k]));
if(td>d[i]){
d[i]=td;px[i]=tx;py[i]=ty;
}
tx-=dx;ty-=dy;
}
}
delta*=0.9;
}
double ans=0;int ind=0;
for(int i=0;i<30;i++){
if(d[i]>ans){
ind=i;
ans=d[i];
}
}
printf("The safest point is (%.1f, %.1f).\n",px[ind],py[ind]);
}
return 0;
}
标签：des blog io ar os sp java for strong
原文地址：http://www.cnblogs.com/xuesu/p/4111837.html
