Method dot

Dynamic Programming Optimizations/Persistent CHT.cpp:4–6

  int x, y;
  PT(int x = 0, int y = 0): x(x), y(y) {}
  friend ll dot(PT &a, PT &b) {
    return 1ll * a.x * b.x + 1ll * a.y * b.y;
  }
  friend int orientation(PT &a, PT &b, PT &c) {
    ll s = 1ll * (b.x - a.x) * (c.y - a.y) - 1ll * (b.y - a.y) * (c.x - a.x);
    return (s > 0) - (s < 0);