POJ 2540 Hotter Colder

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#include<vector>
#include<deque>
#include<queue>

using namespace std;
#define FOR(i,a,b) for(int (i)=(a);(i)<=(b);(i)++)
#define DOR(i,a,b) for(int (i)=(a);(i)>=(b);(i)--)

#define oo 1e6
#define eps 1e-8
#define nMax 100000
#define pb push_back
#define pf push_front

#define F first
#define S second

#define bug puts("OOOOh.....");
#define zero(x) (((x)>0?(x):-(x))<eps)

#define LL long long
#define DB double

int dcmp(double x){
if(fabs(x)<eps) return 0;
return x>0?1:-1;
}
class point {
public:
double x,y;
point (double x=0,double y=0):x(x),y(y) {}
void make(double _x,double _y) {x=_x;y=_y;}
void read() { scanf("%lf%lf",&x,&y); }
void out() { printf("%.2lf %.2lf\n",x,y);}
double len() { return sqrt(x*x+y*y); }
point friend operator - (point const& u,point const& v) {
return point(u.x-v.x,u.y-v.y);
}
point friend operator + (point const& u,point const& v) {
return point(u.x+v.x,u.y+v.y);
}
double friend operator * (point const& u,point const& v) {
return u.x*v.y-u.y*v.x;
}
double friend operator ^ (point const& u,point const& v) {
return u.x*v.x+u.y*v.y;
}
point friend operator * (point const& u,double const& k) {
return point(u.x*k,u.y*k);
}
friend bool operator < (point const& u,point const& v){
if(dcmp(v.x-u.x)==0) return dcmp(u.y-v.y)<0;
return dcmp(u.x-v.x)<0;
}
friend bool operator != (point const& u,point const& v){
return dcmp(u.x-v.x) || dcmp(u.y-v.y);
}
};
double const pi = acos(-1.0);
typedef point vec;

typedef class HalfPlane{
public:
point P,a;
vec V;
double arg,len;
HalfPlane(){};
HalfPlane(point a,point b):a(a){
V = b-a;
P = a;
arg = atan2(V.y,V.x);
len = V.len();
}
void forward(double l){
P = point(-V.y,V.x)*(l/len) + a;
}
} HP;

void init(vector<point> &v) {
v.pb(point(0,0));
v.pb(point(10,0));
v.pb(point(10,10));
v.pb(point(0,10));
return ;
}
int  satisfy(HP u, point a){
return dcmp(u.V*(a-u.P)) >= 0;
}
int cmp(HP a,HP b){
int ret = dcmp(a.arg-b.arg);
if(ret == 0) return satisfy(b,a.P);
return ret < 0;
}
int parrell(HP a,HP b){
return dcmp(a.V*b.V) == 0;
}
int same_dir(HP a,HP b){
return dcmp(a.V ^ b.V) >= 0;
}
int Same(HP a,HP b){
return (dcmp((a.P-b.P)*a.V)==0);
}
point Intersection(HP a,HP b){
point u = a.P-b.P;
double t = (b.V*u)/(a.V*b.V);
return a.P + a.V*t;
}
int in_line(point p,HP l){
return dcmp((p-l.P)^(l.V+l.P-p)) > 0;
}
int cut(vector<point> &u,HP l){
vector<point> ret ;

ret.clear();
u.pb(u[0]);

for(int i=1;i<u.size();i++) {
HP r(u[i-1],u[i]);
//printf("--- ");r.P.out(),r.V.out();
if(parrell(l,r)) {
if(!same_dir(l,r) && !satisfy(l,r.P)) return 0;
}else {
point q = Intersection(l,r);
//printf("Point : ");q.out();
if(in_line(q,r)) ret.pb(q);
}
if(satisfy(l,u[i])) ret.pb(u[i]);
}

u=ret;
if(u.size() < 1) return 0;
return 1;
}
double Area(vector<point> u){
double ret = 0.0;
for(int i=1;i<u.size()-1;i++) ret += (u[i]-u[0])*(u[i+1]-u[i])*0.5;
return ret;
}
vector<point> v;
point p[nMax];
point mid,r,ret;
int n;
char st[40];

int main(){
#ifndef ONLINE_JUDGE
freopen("input.txt","r",stdin);
//	freopen("D1.sol","w",stdout);
#endif
p[0]=point(0,0);
n = 1;
v.clear();
init(v);
int d=1;
while(~scanf("%lf%lf%s",&p
.x,&p
.y,st)){
mid = p
+p[n-1];
mid = mid*0.5;
r = p
-mid;
if(d==0) {
printf("0.00\n");
n++;
continue;
}
if(strcmp(st,"Colder")==0) {
d = d && cut(v,HP(mid,point(-r.y,r.x)+mid));
}else if(strcmp(st,"Hotter")==0) {
d = d && cut(v,HP(mid,point(r.y,-r.x)+mid));
}else {
d = d && cut(v,HP(mid,point(-r.y,r.x)+mid));
if(d)
d = d && cut(v,HP(mid,point(r.y,-r.x)+mid));
}
//	printf("l = %d\n",(int)v.size());
//	for(int i=0;i<v.size();i++) v[i].out();
if(d) {
printf("%.2f\n",Area(v));
}else {
printf("0.00\n");
}
n++;
}
return 0;
}