POJ 1269

#include <cmath>
#include <cstdio>
#include <utility>
using namespace std;
typedef double ld;

int n;

struct Point{
int x, y;
void read(){
scanf("%d%d", &x, &y);
}
}s1, e1, s2, e2;

typedef pair<pair<int, int>, int> Line;
Line a, b;

bool operator == (pair<int, int> &a, pair<int, int> &b){
return a.first == b.first && a.second == b.second;
}

inline int gcd(int a, int b){return b ? gcd(b, a % b) : a;}

Line getLine(Point &a, Point &b){
if(a.x == b.x) return make_pair(make_pair(0, 0), a.x);
if(a.y == b.y) return make_pair(make_pair(1, 0), a.y);
int dx = a.x - b.x, dy = a.y - b.y;
if(dx < 0){
dx *= -1;
dy *= -1;
}
int d = gcd(abs(dx), abs(dy));
dx /= d;
dy /= d;
int v = (a.y % dy + dy) % dy;
v = a.x + (v - a.y) / dy * dx;
return make_pair(make_pair(dx, dy), v);
}

int main(){
puts("INTERSECTING LINES OUTPUT");
scanf("%d", &n);
while(n--){
s1.read();
e1.read();
s2.read();
e2.read();
a = getLine(s1, e1);
b = getLine(s2, e2);
if(a.first == b.first){
if(a.second == b.second) puts("LINE");
else puts("NONE");
}else{
if(a.first == make_pair(0, 0)){
ld k2 = (ld)b.first.second / b.first.first;
ld b2 = (ld)s2.y - k2 * s2.x;
printf("POINT %.2lf %.2lf\n", (ld)s1.x, s1.x * k2 + b2);
}else{
if(b.first == make_pair(0, 0)){
ld k1 = (ld)a.first.second / a.first.first;
ld b1 = (ld)s1.y - k1 * s1.x;
printf("POINT %.2lf %.2lf\n", (ld)s2.x, s2.x * k1 + b1);
}
else{
ld k1 = (ld)a.first.second / a.first.first;
ld b1 = (ld)s1.y - k1 * s1.x;
ld k2 = (ld)b.first.second / b.first.first;
ld b2 = (ld)s2.y - k2 * s2.x;
ld x = (b2 - b1) / (k1 - k2);
printf("POINT %.2lf %.2lf\n", x, x * k1 + b1);
}
}
}
}
puts("END OF OUTPUT");
return 0;
}