Han Solo and Lazer Gun Solution | Codeforces Problem Solved

The full problem statement is here.

Solution to this problem is :

#include <bits/stdc++.h>
using namespace std;

struct point {
    int x, y;
    point (int x, int y) : x(x), y(y) {}
    point () {}
    void in () {
        cin >> x >> y;
    }
    bool operator < (point p) const {
        if(x == p.x) return (y < p.y);
        return x < p.x;
    }
};
map <point, int> f;

int pos(int x) {
    return (x < 0) ? -x : x;
}
point normal(int x, int y) {
    if(y < 0) {
        x *= -1;
        y *= -1;
    }
    if(y == 0) {
        if(x < 0) x *= -1;
    }
    int d = __gcd(pos(x), pos(y));
    return point(x / d, y / d);
}

int main()
{
    ios_base :: sync_with_stdio (0);
    cin.tie(0);

    int n;
    cin >> n;

    point o;
    o.in();

    int ans = 0;
    for(int i = 1; i <= n; i++) {
        point p;
        p.in();
        p = normal(p.x - o.x, p.y - o.y);

        if(f[p] == 0) {
            ans += 1;
            f[p] = 1;
        }
    }
    cout << ans << endl;
    return 0;
}