mirror of
https://github.com/Kiritow/OJ-Problems-Source.git
synced 2024-03-22 13:11:29 +08:00
114 lines
2.9 KiB
C++
114 lines
2.9 KiB
C++
#include <algorithm>
|
|
#include <iostream>
|
|
#include <cstdlib>
|
|
#include <cstdio>
|
|
#include <cmath>
|
|
using namespace std;
|
|
typedef struct p1node
|
|
{
|
|
double a,b,c,d;
|
|
}plane;
|
|
plane Pl;
|
|
typedef struct p2node
|
|
{
|
|
double x,y,z;
|
|
}point;
|
|
point temp;
|
|
point P[ 105 ];
|
|
point S[ 105 ];
|
|
int shadow( plane p, point s, int n )
|
|
{
|
|
double D = p.a*s.x+p.b*s.y+p.c*s.z;
|
|
if ( D-p.d < 0 ) {
|
|
p.a *= -1;p.b *= -1;p.c *= -1;
|
|
p.d *= -1;
|
|
D *= -1;
|
|
}
|
|
int count = 0;
|
|
for ( int i = 0 ; i < n ; ++ i ) {
|
|
double det = p.a*P[i].x+p.b*P[i].y+p.c*P[i].z-D;
|
|
if ( det < 0 ) count ++;
|
|
}
|
|
if ( count == 0 ) return 0;
|
|
if ( count != n ) return n+1;
|
|
for ( int i = 0 ; i < n ; ++ i ) {
|
|
double dx = P[i].x - s.x;
|
|
double dy = P[i].y - s.y;
|
|
double dz = P[i].z - s.z;
|
|
double t = (p.d-p.a*s.x-p.b*s.y-p.c*s.z)/(p.a*dx+p.b*dy+p.c*dz);
|
|
P[i].x = s.x + t*dx;
|
|
P[i].y = s.y + t*dy;
|
|
P[i].z = s.z + t*dz;
|
|
}
|
|
return n;
|
|
}
|
|
void change( plane p, int n )
|
|
{
|
|
if ( p.a*p.a + p.b*p.b == 0 ) return;
|
|
for ( int i = 0 ; i < n ; ++ i ) {
|
|
double cosC = p.b/sqrt(p.a*p.a+p.b*p.b);
|
|
double sinC = p.a/sqrt(p.a*p.a+p.b*p.b);
|
|
temp.x = P[i].x*cosC-P[i].y*sinC;
|
|
temp.y = P[i].x*sinC+P[i].y*cosC;
|
|
temp.z = P[i].z;
|
|
P[i] = temp;
|
|
double cosA = p.c/sqrt(p.a*p.a+p.b*p.b+p.c*p.c);
|
|
double sinA = sqrt(p.a*p.a+p.b*p.b)/sqrt(p.a*p.a+p.b*p.b+p.c*p.c);
|
|
temp.x = P[i].x;
|
|
temp.y = P[i].y*cosA-P[i].z*sinA;
|
|
temp.z = P[i].y*sinA+P[i].z*cosA;
|
|
P[i] = temp;
|
|
}
|
|
}
|
|
double crossproduct( point a, point b, point c )
|
|
{
|
|
return (b.x-a.x)*(c.y-a.y)-(c.x-a.x)*(b.y-a.y);
|
|
}
|
|
bool cmp1( point a, point b )
|
|
{
|
|
if ( a.x == b.x )
|
|
return a.y < b.y;
|
|
return a.x < b.x;
|
|
}
|
|
bool cmp2( point a, point b )
|
|
{
|
|
return crossproduct( P[0], a, b )>0;
|
|
}
|
|
void Graham( int n )
|
|
{
|
|
sort( P+0, P+n, cmp1 );
|
|
sort( P+1, P+n, cmp2 );
|
|
int top = -1;
|
|
if ( n > 0 ) S[++ top] = P[0];
|
|
if ( n > 1 ) S[++ top] = P[1];
|
|
if ( n > 2 ) {
|
|
for ( int i = 2 ; i < n ; ++ i ) {
|
|
while ( crossproduct( S[top-1], S[top], P[i] ) < 0 ) -- top;
|
|
S[++ top] = P[i];
|
|
}
|
|
}
|
|
double area = 0.0;
|
|
for ( int i = 2 ; i <= top ; ++ i )
|
|
area += crossproduct( S[0], S[i-1], S[i] );
|
|
printf("%.2lf\n",area*0.5);
|
|
}
|
|
int main()
|
|
{
|
|
int n;
|
|
while ( cin >> Pl.a >> Pl.b >> Pl.c >> Pl.d ) {
|
|
if ( Pl.a == 0 && Pl.b == 0 && Pl.c == 0 ) break;
|
|
cin >> n;
|
|
for ( int i = 0 ; i <= n ; ++ i )
|
|
cin >> P[i].x >> P[i].y >> P[i].z;
|
|
int s_count = shadow( Pl, P[n], n );
|
|
if ( !s_ )
|
|
cout << "0.00" << endl;
|
|
else if ( s_count > n )
|
|
cout << "Infi" << endl;
|
|
else {
|
|
change( Pl, s_ );
|
|
Graham( s_ );
|
|
}
|
|
}
|
|
}
|