hdu 5033 Building 几何+单调栈

来源：互联网发布：vasp linux 编辑：程序博客网时间：2024/05/17 06:52
大概用一个单调栈存一下大楼的编号以及这个大楼可以控制的范围....然后乱搞一下...被虐了一下午精神有点恍惚，先贴代码，具体思路闲了再补......WA了一下午，晚上加了四行直接过了......
#include <iostream>#include <cstdio>#include <algorithm>#include <cstring>#include <string>#include <cmath>#include <vector>#include <stack>typedef double type;using namespace std;const double PI=acos(-1.0);const double eps=1e-5;const double inf=1e18;struct Point{    type x,y;    Point(){}    Point(type a,type b)    {        x=a;        y=b;    }    void read()    {        scanf("%lf%lf",&x,&y);    }    void print()    {        printf("%.6lf %.6lf\n",x,y);    }};typedef Point Vector;Vector operator + (Vector A,Vector B){    return Vector(A.x+B.x,A.y+B.y);}Vector operator - (Point A,Point B){    return Vector(A.x-B.x,A.y-B.y);}Vector operator * (Vector A,type p){    return Vector(A.x*p,A.y*p);}Vector operator / (Vector A,type p){    return Vector(A.x/p,A.y/p);}bool operator < (const Point &a,const Point &b){   return a.x<b.x;   // return a.x<b.x || (a.x==b.x && a.y<b.y);}int dcmp(double x){    if (fabs(x)<eps) return 0;    else return x<0?-1:1;}bool operator == (const Point& a,const Point b){    return dcmp(a.x-b.x)==0 && dcmp(a.y-b.y)==0;}//atan2(x,y) :向量(x,y)的极角，即从x轴正半轴旋转到该向量方向所需要的角度。type Dot(Vector A,Vector B){    return A.x*B.x+A.y*B.y;}type Cross(Vector A,Vector B){    return A.x*B.y-A.y*B.x;}type Length(Vector A){    return sqrt(Dot(A,A));}type Angle(Vector A,Vector B){    return acos(Dot(A,B))/Length(A)/Length(B);}type Area2(Point A,Point B,Point C){    return Cross(B-A,C-A);}Vector Rotate(Vector A,double rad){    return Vector(A.x*cos(rad)-A.y*sin(rad),A.x*sin(rad)+A.y*cos(rad));}Vector Normal(Vector A)//单位法线,左转90度，长度归一{    double L=Length(A);    return Vector(-A.y/L,A.x/L);}Point GetLineIntersection(Point P,Vector v,Point Q,Vector w){    Vector u=P-Q;    double t=Cross(w,u)/Cross(v,w);    return P+v*t;}const int maxn=500050;int n,m;Point p[maxn];int lt[maxn],rt[maxn];struct query{    double x;    int id;}qy[maxn];bool cmpx(query a,query b){    return a.x<b.x;}bool cmpid(query a,query b){    return a.id<b.id;}struct node{    int x;    double pos;    node(int xx,double y)    {        x=xx;        pos=y;    }    node()    {    }};int main(){//    freopen("in.txt","r",stdin);    int tt;    int cnt=0;    scanf("%d",&tt);    while(tt--)    {        memset(lt,-1,sizeof lt);        memset(rt,-1,sizeof rt);        scanf("%d",&n);        for (int i=0; i<n; i++)        p[i].read();        sort(p,p+n);        scanf("%d",&m);        for (int i=0; i<m; i++)        {            scanf("%lf",&qy[i].x);            qy[i].id=i;        }        sort(qy,qy+m,cmpx);        stack<node> s;        while(!s.empty()) s.pop();        int i=-1,j=0;        Point ins;        for (j=0; j<m; j++)        {            double v=qy[j].x;            int id;            while (i+1<n && dcmp(p[i+1].x-v)==-1)            {                i++;                while(!s.empty())                {                    id=s.top().x;                    if (dcmp(p[id].y-p[i].y)!=1) s.pop();                    else break;                }                if (s.empty())                {                    s.push(node(i,inf));                }                else                {                    while(!s.empty())                    {                        id=s.top().x;                        Point p1=p[id];                        Vector v1=p[i]-p[id];                        Point p2=Point(p[id].x,0);                        Vector v2=Vector(1,0);                        ins=GetLineIntersection(p1,v1,p2,v2);                        if (ins.x<s.top().pos) break;                        else s.pop();                    }                    s.push(node(i,ins.x));                }            }            id=qy[j].id;            while(!s.empty())            {                if (dcmp(s.top().pos-v)==1)                {                    lt[id]=s.top().x;                    break;                }                else s.pop();            }            if (s.empty())            {                lt[id]=-1;            }        }        while(!s.empty()) s.pop();        i=n;        for (j=m-1; j>=0; j--)        {            double v=qy[j].x;            int id;            while(i-1>=0 && dcmp(p[i-1].x-v)==1)            {                i--;                while(!s.empty())                {                    id=s.top().x;                    if (dcmp(p[id].y-p[i].y)!=1)s.pop();                    else break;                }                if (s.empty())                {                        s.push(node(i,-inf));                }                else                {                    while(!s.empty())                    {                        id=s.top().x;                        Point p1=p[id];                        Vector v1=p[i]-p[id];                        Point p2=Point(p[id].x,0);                        Vector v2=Vector(-1,0);                        ins=GetLineIntersection(p1,v1,p2,v2);                        if (ins.x>s.top().pos) break;                        else s.pop();                    }                    s.push(node(i,ins.x));                }            }            id=qy[j].id;            while(!s.empty())            {                if (dcmp(s.top().pos-v)==-1)                {                    rt[id]=s.top().x;                    break;                }                else s.pop();            }            if (s.empty()) rt[id]=-1;        }        printf("Case #%d:\n",++cnt);        sort(qy,qy+m,cmpid);        for (int i=0; i<m; i++)        {            double a1,a2;            Vector v1,v2;            v2=Vector(0.0,1.0);            if (lt[i]==-1) a1=90.0;            else            {                v1=p[lt[i]]-Point(qy[i].x,0);                v1=v1/Length(v1);                a1=Angle(v1,v2)*180.0/PI;            }            if (rt[i]==-1) a2=90.0;            else            {                v1=p[rt[i]]-Point(qy[i].x,0);                v1=v1/Length(v1);                a2=Angle(v1,v2)*180.0/PI;            }            printf("%.12lf\n",a1+a2);        }    }    return 0;}
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