uva 1421 Archery

来源：互联网发布：linux怎么粘贴编辑：程序博客网时间：2024/06/07 10:07

#include<cstdio>#include<cstring>#include<algorithm>#include<cmath>#define eps 1e-6#define MAX(x,y) ((x)>(y)?(x):(y))#define MIN(x,y) ((x)>(y)?(y):(x))using namespace std;struct node{double l,r,h;}line[5050];int n;int ok(double x){double L=atan2(line[0].h,line[0].r-x);double R=atan2(line[0].h,line[0].l-x);for(int i=1;i<n;i++){double L1=atan2(line[i].h,line[i].r-x);    double R1=atan2(line[i].h,line[i].l-x);    if(L-R1>eps)    return -1;    if(L1-R>eps)    return 1;    L=MAX(L,L1);    R=MIN(R,R1);}return 0;}bool cmp(const node &a,const node &b){return a.h<b.h;}int main(){int T;double w; scanf("%d",&T);while(T--){scanf("%lf%d",&w,&n);for(int i=0;i<n;i++)scanf("%lf%lf%lf",&line[i].h,&line[i].l,&line[i].r);sort(line,line+n,cmp);double l=0,r=w;int flag=0;while(r-l>eps){double m=(l+r)/2;int t=ok(m);if(t==1)l=m;elseif(t==-1)r=m;else{flag=1;break;} }if(flag)printf("YES\n");elseprintf("NO\n");}}

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