103 lines
2.8 KiB
C++
103 lines
2.8 KiB
C++
#include <iostream>
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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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const double EPS=1e-8;
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const int maxn=100;
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int n;
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struct Point
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{
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double x,y;
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Point (double x=0,double y=0):x(x),y(y){}
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};
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Point poly[maxn];
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typedef Point Vector;
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Vector operator + (Vector A,Vector B) {return Vector(A.x+B.x,A.y+B.y);}
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Vector operator - (Point A,Point B) {return Vector(A.x-B.x,A.y-B.y);}
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Vector operator * (Vector A,double p) {return Vector(A.x*p,A.y*p);}
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Vector operator / (Vector A,double p) {return Vector(A.x/p,A.y/p);}
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bool operator < (const Point &a,const Point &b){
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return a.x < b.x ||(a.x==b.x &&a.y < b.y);
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}
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int dcmp (double x){
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if(fabs(x)<EPS)
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return 0;
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else return x < 0?-1:1;
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}
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bool operator == (const Point &a ,const Point &b){
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return dcmp(a.x-b.x) ==0 && dcmp(a.y - b.y)==0;
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}
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double Cross (Vector A,Vector B) {return A.x*B.y - A.y*B.x;}
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double Dot (Vector A,Vector B) {return A.x*B.x + A.y*B.y;}
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bool isPointOnSegment (Point p,Point a1,Point a2)
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{
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return dcmp ( Cross(a1-p,a2-p) )==0 && dcmp(Dot (a1-p,a2-p))<0;
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}
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int online(Point a,Point b,Point p)
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{
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Point v1,v2;
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v1=p-a;v2=p-b;
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if( dcmp(Cross(v1,v2))!=0) //绉涓涓0 灏变ㄧ寸嚎涓
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return 0;
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else
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{
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if(dcmp(min(a.x,b.x)- p.x)<=0 && dcmp(p.x-max(a.x,b.x))<=0
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&&dcmp(min(a.y,b.y)- p.y)<=0 &&dcmp( p.y-max(a.y,b.y))<=0)
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return 1;
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else
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return 0;
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}
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}
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int isPointInPolygon (Point p)
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{
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int wn=0;
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for(int i=0;i<n;i++){
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if( online (poly[i], poly[(i+1)%n],p)) return 0;
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int k=dcmp (Cross(poly[(i+1)%n]-poly[i],p-poly[i]));
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int d1=dcmp(poly[i].y-p.y);
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int d2=dcmp(poly[(i+1)%n].y-p.y);
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if(k>0 && d1<=0 && d2>0) wn++;
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if(k<0 && d2<=0 && d1>0) wn--;
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}
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if(wn!=0) return 1;
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return 0;
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}
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int main()
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{
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double v,b,g;
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while (scanf("%lf %lf %lf",&v,&b,&g),v||b||g)
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{
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v=-v;
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scanf("%d",&n);
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bool flag=false;
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int i;
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double minx=1e12,maxx=-1e12,maxy=-1e12;
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for(i=0;i<n;i++)
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{
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scanf("%lf %lf",&poly[i].x,&poly[i].y);
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if(poly[i].x>maxx) maxx=poly[i].x;
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if(poly[i].x<minx) minx=poly[i].x;
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if(poly[i].y>maxy) maxy=poly[i].y;
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}
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double t;
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for(int i=0;;i++)
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{
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t=i*0.001;
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Point temp;
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temp.x=v*t;temp.y=b*t-0.5*g*t*t;
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if( isPointInPolygon(temp) )
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{
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printf("%.2f\n",t-EPS);
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flag=true;
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break;
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}
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if(!g && temp.y>maxy) break;
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if(temp.y<0) break;
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}
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if(!flag) printf("Miss!\n");
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}
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return 0;
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}
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