constexpr auto EPS = numeric_limits::epsilon(); struct point { ll x, y; point() { x = y = 0; } point(ll _x, ll _y) : x(_x), y(_y) {} bool operator < (point p) const { return (x == p.x && y < p.y) || x < p.x; } bool operator == (point p) const { return x == p.x && y == p.y; } }; double dist(point& p1, point& p2) { return hypot(p1.x - p2.x, p1.y - p2.y); } struct vec { ll x, y; vec(ll _x, ll _y) : x(_x), y(_y) {} vec(point a, point b) { x = b.x - a.x, y = b.y - a.y; } }; ll dot(vec a, vec b) { return a.x * b.x + a.y * b.y; } ll norm_sq(vec v) { return v.x * v.x + v.y * v.y; } ll cross(vec a, vec b) { return a.x * b.y - a.y * b.x; } double angle(point a, point o, point b) { vec oa(o, a), ob(o, b); return acos(dot(oa, ob) / sqrt(norm_sq(oa) * norm_sq(ob))); } // (q.x - p.x) * (r.y - p.y) - (r.x - p.x) * (q.y - p.y) bool ccw(point p, point q, point r) { return cross(vec(p, q), vec(p, r)) > 0; } struct line { ll a, b, c; bool operator < (const line& l) const { return tie(a, b, c) < tie(l.a, l.b, l.c); } line(point p1, point p2) { a = p2.y - p1.y, b = p1.x - p2.x, c = p1.y * p2.x - p1.x * p2.y; ll d = __gcd(__gcd(abs(a), abs(b)), abs(c)); a /= d, b /= d, c /= d; } }; double point_to_line(point p, line l) { return abs(l.a * p.x + l.b * p.y + l.c) / hypot(l.a, l.b); } line perp_bi(point p1, point p2) { ll a = 2 * (p2.x - p1.x), b = 2 * (p2.y - p1.y), c = -a * (p1.x + p2.x) / 2 - b * (p1.y + p2.y) / 2; ll d = __gcd(__gcd(abs(a), abs(b)), abs(c)); return { a / d, b / d, c / d }; } point reflect(point p, line l) { ll x = p.x * (l.b * l.b - l.a * l.a) - 2 * l.a * (l.b * p.y + l.c); ll y = p.y * (l.a * l.a - l.b * l.b) - 2 * l.b * (l.a * p.x + l.c); ll d = l.a * l.a + l.b * l.b; if (x % d && y % d) return { 10001, 10001 }; else return { x / d, y / d }; } struct seg { point p1, p2; seg(point _p1, point _p2) : p1(_p1), p2(_p2) {} }; line::line(seg s) { line(s.p1, s.p2); } double point_to_seg(point p, seg s) { ll a = norm_sq(to_vec(s.p1, s.p2)), b = norm_sq(to_vec(p, s.p1)), c = norm_sq(to_vec(p, s.p2)); if (a + b > c && a + c > b) return point_to_line(p, to_line(s)); else return min(dist(p, s.p1), dist(p, s.p2)); } bool seg_isect(seg a, seg b) { return ccw(a.p1, a.p2, b.p1) * ccw(a.p1, a.p2, b.p2) <= 0 && ccw(b.p1, b.p2, a.p1) * ccw(b.p1, b.p2, a.p2) <= 0); }