hdoj_1007 Quoit Design

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题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=1007

题目大意：最近点对问题

//C++代码#include<iostream>#include<algorithm>#include<cstdio>#include<cmath>using namespace std;struct Point{double x,y;}p[100005],q[100005];bool xcmp(Point a,Point b){return a.x<b.x;}bool ycmp(Point a,Point b){return a.y<b.y;}double dist2(Point a,Point b){return (a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y);}double min(double a,double b){return a<b? a:b;}double solve(int l,int r){if(r-l==1) return dist2(p[l],p[r]);if(r-l==2) return min(min(dist2(p[l],p[l+1]),dist2(p[l],p[r])),dist2(p[l+1],p[r]));int m=(l+r)/2;double curmin=min(solve(l,m),solve(m+1,r));int i,j,num=0;for(i=l;i<=r;i++){if(abs(p[i].x-p[m].x)<curmin) q[num++]=p[i];}sort(q,q+num,ycmp);for(i=0;i<num-1;i++){for(j=i+1;j<num && q[j].y-q[i].y<curmin;j++){if(dist2(q[i],q[j])<curmin) curmin=dist2(q[i],q[j]);}}return curmin;}int main(){int n;while(scanf("%d",&n)!=EOF){if(n==0) break;for(int i=0;i<n;i++) scanf("%lf%lf",&p[i].x,&p[i].y);sort(p,p+n,xcmp);printf("%.2lf\n",sqrt(solve(0,n-1))/2);}return 0;}