#ifndef _MYGRAPH
#define _MYGRAPH
class node
{
public:
node* next;
int index;
};
//build a graph with n vertice
node* build_graph(int n);
//connect index a to index b of graph
void graph_connect(node* graph,int a,int b);
//show graph connecting information
void show_graph(node* graph,int n);
//check whether vertex a connects to vertex b
bool query_connect(node* graph,int a, int b);
#endif
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