// Graph ADT interface ... COMP2521 
#include <stdbool.h>

typedef struct GraphRep *Graph;

// vertices are ints
typedef int Vertex;

// edges are pairs of vertices (end-points)
typedef struct Edge {
   Vertex v;
   Vertex w;
} Edge;

Graph newGraph(int);
void  insertEdge(Graph, Edge);
void  removeEdge(Graph, Edge);
bool  adjacent(Graph, Vertex, Vertex);
void  showGraph(Graph);
void  freeGraph(Graph);


// By 
//  .----------------.  .----------------.  .----------------.  .-----------------.  .----------------.  .----------------. 
// | .--------------. || .--------------. || .--------------. || .--------------. | | .--------------. || .--------------. |
// | |  _________   | || | _____  _____ | || |      __      | || | ____  _____  | | | |  ____  ____  | || |     ____     | |
// | | |  _   _  |  | || ||_   _||_   _|| || |     /  \     | || ||_   \|_   _| | | | | |_   ||   _| | || |   .'    `.   | |
// | | |_/ | | \_|  | || |  | |    | |  | || |    / /\ \    | || |  |   \ | |   | | | |   | |__| |   | || |  /  .--.  \  | |
// | |     | |      | || |  | '    ' |  | || |   / ____ \   | || |  | |\ \| |   | | | |   |  __  |   | || |  | |    | |  | |
// | |    _| |_     | || |   \ `--' /   | || | _/ /    \ \_ | || | _| |_\   |_  | | | |  _| |  | |_  | || |  \  `--'  /  | |
// | |   |_____|    | || |    `.__.'    | || ||____|  |____|| || ||_____|\____| | | | | |____||____| | || |   `.____.'   | |
// | |              | || |              | || |              | || |              | | | |              | || |              | |
// | '--------------' || '--------------' || '--------------' || '--------------' | | '--------------' || '--------------' |
//  '----------------'  '----------------'  '----------------'  '----------------'   '----------------'  '----------------' 
 
//  Email :    z5261243@unsw.edu.au
//             hhoanhtuann@gmail.com