uva 10084

首次6小時 獻給的半平面交

//
//        GGGGGGGGGGGGG        CCCCCCCCCCCCC               AAA
//     GGG::::::::::::G     CCC::::::::::::C              A:::A
//   GG:::::::::::::::G   CC:::::::::::::::C             A:::::A
//  G:::::GGGGGGGG::::G  C:::::CCCCCCCC::::C            A:::::::A
// G:::::G       GGGGGG C:::::C       CCCCCC           A:::::::::A
//G:::::G              C:::::C                        A:::::A:::::A
//G:::::G              C:::::C                       A:::::A A:::::A
//G:::::G    GGGGGGGGGGC:::::C                      A:::::A   A:::::A
//G:::::G    G::::::::GC:::::C                     A:::::A     A:::::A
//G:::::G    GGGGG::::GC:::::C                    A:::::AAAAAAAAA:::::A
//G:::::G        G::::GC:::::C                   A:::::::::::::::::::::A
// G:::::G       G::::G C:::::C       CCCCCC    A:::::AAAAAAAAAAAAA:::::A
//  G:::::GGGGGGGG::::G  C:::::CCCCCCCC::::C   A:::::A             A:::::A
//   GG:::::::::::::::G   CC:::::::::::::::C  A:::::A               A:::::A
//     GGG::::::GGG:::G     CCC::::::::::::C A:::::A                 A:::::A
//        GGGGGG   GGGG        CCCCCCCCCCCCCAAAAAAA                   AAAAAAA
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <complex>
#include <climits>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <cctype>
#include <utility>
#include <ctime>
using namespace std;
#ifdef DEBUG
#define VAR(a,b) decltype(b) a=(b)
#define debug(...) printf("DEBUG: "),printf(__VA_ARGS__)
#define gettime() end_time=clock();printf("now running time is %.7f\n",(float)(end_time - start_time)/CLOCKS_PER_SEC);
#else
#define VAR(a,b) __typeof(b) a=(b)
#define debug(...)
#define gettime()
#endif
typedef unsigned int uint;
typedef long long int Int;
typedef unsigned long long int UInt;
#define Set(a,s) memset(a,s,sizeof(a))
#define Write(w) freopen(w,"w",stdout)
#define Read(r) freopen(r,"r",stdin)
#define Pln() printf("\n")
#define I_de(x,n)for(int i=0;i<n;i++)printf("%d ",x[i]);Pln()
#define De(x)printf(#x"%d\n",x)
#define For(i,x)for(int i=0;i<x;i++)
#define CON(x,y) x##y
#define Pmz(dp,nx,ny)for(int hty=0;hty<ny;hty++){for(int htx=0;htx<nx;htx++){\
    printf("%d ",dp[htx][hty]);}Pln();}
#define M 30005
#define PII pair<int,int>
#define PB push_back
#define oo INT_MAX
#define Set_oo 0x3f
#define FOR(a,b) for(VAR(a,(b).begin());a!=(b).end();++a)
#define eps 1e-6
clock_t start_time=clock(), end_time;
bool xdy(double x,double y){return x>y+eps;}
bool xddy(double x,double y){return x>y-eps;}
bool xcy(double x,double y){return x<y-eps;}
bool xcdy(double x,double y){return x<y+eps;}
bool xeqy(double x,double y){return fabs(x-y)<eps;}
int min3(int x,int y,int z){
    int tmp=min(x,y);
    return min(tmp,z);
}
int max3(int x,int y,int z){
    int tmp=max(x,y);
    return max(tmp,z);
}
typedef complex<double> point;
struct line{
    point a,b;
};
#define x real()
#define y imag()
typedef vector<point> poly;
double cross(point o,point a,point b){
//    debug("po %lf %lf\n",o.x,o.y);
    return (a.x-o.x)*(b.y-o.y)-(a.y-o.y)*(b.x-o.x);
}
double cross(point a,point b){
    return a.x*b.y-a.y*b.x;
}
double area(poly p){
    double ar=0;
    int size=p.size();
    for(int i=0;i<size;i++){
//        debug("%lf %lf\n",p[i].x,p[i].y);
        ar+=cross(p[i],p[(i+1)%size]);
    }//Pln();
    return fabs(ar)/2;

}
point intersection(point a1,point a2,point b1,point b2){
    point a=a2-a1,b=b2-b1,s=b1-a1;
    return a1+a*cross(b,s)/cross(b,a);
}
poly halfplane(poly p,line& lin,int fg){
    poly q;
    point p1=lin.a,p2=lin.b;

    int n=p.size();
    for(int i=0;i<n;i++){
        double c=cross(p1,p2,p[i]);
        int t=(i+1)%n;
        double d=cross(p1,p2,p[t]);
//        debug("%lf %lf\n",c,d);
        if(c*fg>=0)q.PB(p[i]);
        if(c*d<0)q.PB(intersection(p1,p2,p[i],p[t]));
    }
    return q;
}
double lx,ly,nx,ny;
char cmd[50];
poly p;
void init(){
    p.PB(point(0.0,0.0));
    p.PB(point(10.0,0.0));
    p.PB(point(10.0,10.0));
    p.PB(point(0.0,10.0));
}
int main() {
    ios_base::sync_with_stdio(0);
    lx=ly=0.0;
    init();
    bool isover=false;
    while(~scanf("%lf%lf%s",&nx,&ny,cmd)){
        line l;
        int fg=1;
        point cm=point((nx+lx)/2,(ny+ly)/2);
        point acm=point(cm.x-ly+ny,cm.y+lx-nx);
        if(!strcmp(cmd,"Same")){
            p.clear();
        }else if(!strcmp(cmd,"Hotter")){
            if(cross(acm-cm,point(lx-cm.x,ly-cm.y))>0){
                fg=-1;
            }
        }else{
            if(cross(acm-cm,point(lx-cm.x,ly-cm.y))<0){
                fg=-1;
            }
        }
        l.a=cm;
        l.b=acm;
        p=halfplane(p,l,fg);
        printf("%.2f\n",area(p));

        lx=nx;ly=ny;




    }
















}