试在邻接矩阵存储结构上实现图的基本操作 matrix_insert_vertex 和matrix_insert_arc,相关定义如下:
typedef int VertexType;
typedef enum{
DG, UDG
}GraphType;
typedef struct{
VertexType vertex[MAX_VERTEX_NUM]; //顶点向量
int arcs[MAX_VERTEX_NUM][MAX_VERTEX_NUM]; //邻接矩阵
int vexnum, arcnum; //图的当前顶点数和弧数
GraphType type; //图的种类标志
}MatrixGraph;
int matrix_locate_vertex(MatrixGraph MG, VertexType vex); //返回顶点 v 在vertex数组中的下标,如果v不存在,返回-1
bool matrix_insert_vertex(MatrixGraph G, VertexType v);
bool matrix_insert_arc(MatrixGraph *G, VertexType v, VertexType w);
当成功插入顶点或边时,函数返回true,否则(如顶点或边已存在、插入边时顶点v或w不存在)返回false。
bool matrix_insert_vertex(MatrixGraph* G, VertexType v)
{
if (matrix_locate_vertex(G, v) != -1 || G->vexnum + 1 >= MAX_VERTEX_NUM)
return false;
G->vertex[G->vexnum] = v;
G->vexnum++;
for (int i = 0; i < G->vexnum; i++)
G->arcs[i][G->vexnum - 1] = G->arcs[G->vexnum - 1][i] = 0;
return true;
}
bool matrix_insert_arc(MatrixGraph* G, VertexType v, VertexType w)
{
int V = matrix_locate_vertex(G, v);
int W = matrix_locate_vertex(G, w);
if (V == -1 || W == -1)
return false;
if (G->type == "DG") {
if (G->arcs[V][W] == 1)
return false;
G->arcs[V][W] = 1;
} else {
if (G->arcs[V][W] == 1 || G->arcs[W][V] == 1)
return false;
G->arcs[V][W] = G->arcs[W][V] = 1;
}
G->arcnum++;
return true;
}