ref: a0f5762d967c3c09e6d7303e238976c6c9835ed5
dir: /graph/graph.h/
typedef struct Vertex Vertex; typedef struct Vectangle Vectangle; struct Vertex{ int x; int y; }; struct Vectangle{ Vertex min; Vertex max; }; Vertex V(int, int); Vectangle V²(int, int, int, int); Vectangle toV²(Vertex, Vertex); Vertex ΔV(Vertex, Vertex); Vertex ∑V(Vertex, Vertex); int V∩V²(Vertex, Vectangle);