mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
91 lines
3.0 KiB
C++
91 lines
3.0 KiB
C++
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#include <cstdio>
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#include <cstring>
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#include <algorithm>
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#include <cmath>
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using namespace std;
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#define sqr(a) ((a)*(a))
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#define trarea(p) fabs ((vdet(p[0],p[1],p[2])/2.0))
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double const EPS = 1e-12;
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int const maxn = 20011;
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struct point{double x,y;int flag;};
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struct circle{
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point c;
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double r;
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};
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inline double vdet(point op,point p1,point p2){
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return (p1.x-op.x)*(p2.y-op.y)-(p2.x-op.x)*(p1.y-op.y);
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}
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inline double dis(point a,point b){
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return sqr(a.x-b.x)+sqr(a.y-b.y);
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}
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inline point get_out_circle(point p[]){
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double c1,c2,xa,xb,xc,ya,yb,yc;
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point o;
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xa=p[0].x,xb=p[1].x,xc=p[2].x;
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ya = p[0].y,yb = p[1].y,yc = p[2].y;
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c1 = (sqr(xa) + sqr(ya) - sqr(xb) - sqr(yb))/2.0;
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c2 = (sqr(xa) + sqr(ya) - sqr(xc) - sqr(yc))/2.0;
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o.x = (c1*(ya-yc)-c2*(ya-yb))/((xa-xb)*(ya-yc)-(xa-xc)*(ya-yb));
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o.y = (c1*(xa-xc)-c2*(xa-xb))/((ya-yb)*(xa-xc)-(ya-yc)*(xa-xb));
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return o;
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}
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inline double get_out_r(point p[]){
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double a = dis(p[0],p[1]),b = dis(p[1],p[2]),c = dis(p[2],p[0]),s = trarea(p);
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return a*b*c/sqr(4*s);
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}
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point must_on[3],p[maxn];
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circle mc;
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inline void get_circle(int tm){
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switch(tm){
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case 0:mc.r = -1;
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break;
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case 1:mc.r = 0,mc.c = must_on[0];
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break;
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case 2:{
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mc.r = dis(must_on[0],must_on[1])/4.0;
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mc.c.x = (must_on[0].x+must_on[1].x)/2.0;
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mc.c.y = (must_on[0].y + must_on[1].y)/2.0;
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}break;
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case 3:{
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mc.r = get_out_r(must_on);
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mc.c = get_out_circle(must_on);
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}break;
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}
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}
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inline void min_circle(int t,int ton){
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get_circle(ton);
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if(ton >= 3)return;
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for(int i = 0; i < t; ++i){
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if(p[i].flag == 1){
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if(dis(mc.c,p[i]) > mc.r + EPS){
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must_on[ton] = p[i];
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min_circle(i,ton+1);
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}
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}
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else {
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if(dis(mc.c,p[i]) + EPS < mc.r){
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must_on[ton] = p[i];
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min_circle(i,ton+1);
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}
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}
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}
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}
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int main(){
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int n,m;
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while (scanf("%d%d",&n,&m) != EOF){
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for(int i = 0; i < n; ++i){
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scanf("%lf%lf",&p[i].x,&p[i].y);
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p[i].flag = 1;
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}
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for(int i = n; i < m + n; ++i){
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scanf("%lf%lf",&p[i].x,&p[i].y);
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p[i].flag = 2;
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}
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n = n + m;
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random_shuffle(p,p+n);
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min_circle(n,0);
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printf("%.3lf %.3lf\n%.3lf\n",mc.c.x,mc.c.y,sqrt(mc.r));
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}
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return 0;
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}
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