数据结构C:邻接矩阵的创建与普里姆算法(Prim)

#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#define maxSize 5
/* run this program using the console pauser or add your own getch, system("pause") or input loop */
struct VType{
	//顶点的值 
	int no;
};
struct MGraph{
	//邻接矩阵 
	int edges[maxSize][maxSize];
	int n,e;
	//存放顶点信息 
	VType* vtype[maxSize];
};
void printArr(int a[maxSize][maxSize]){
	for(int i = 0;i < maxSize;++i){
		for(int j = 0;j < maxSize;++j){
			printf("%-3d",a[i][j]);
		}
		printf("\n");
	}
}
//创建邻接矩阵
void create(MGraph *&g,int n){
	//1.初始化结构体
	g = (MGraph*)malloc(sizeof(MGraph));
	g->e = 0;
	g->n = n;
	int i;
	//2.while循环,循环创建各个VType结点,并且为顶点的值赋值 
	while(i < maxSize){
		VType* v = (VType*)malloc(sizeof(VType));
		v->no = i;
		g->vtype[i++] = v;
	}
	for(int i = 0;i < maxSize; ++i){
		//这里创建的是无向图,所以是j=i,减少输入 
		for(int j = i;j < maxSize;++j){
			int weight;
			//1.用户输入权值
			//2.给用户显示当前输入的是那个到那个的权值
			//3.如果用户输入了权值为 无穷 则两个结点不相连,无穷使用了 #include <limits.h>这个库的INT_MAX					
			if(i!=j){
				printf("Please input node %d ---> node %d weight\n",i,j);
				printf("If input -1 represent no road from node %d to node %d\n",j,i);
				printf("weight( %d -> %d ):",i,j);
				scanf("%d",&weight); 
				if(weight != -1){
					g->e++;
				}else{
					weight = INT_MAX;
				}
			}
			else{
				weight = 0;
			}
			g->edges[i][j] = weight;
			g->edges[j][i] = weight; 
		}
	} 
	//输出一下看一下 
//	printArr(g->edges);
} 
//普利姆最小生成树算法
void prim(MGraph *g,int v0,int &sum){
	//到树的最小花费数组 
	int lowcost[maxSize];
	//节点访问与否数组 
	int vext[maxSize];
	//刚刚进树的结点 
	int v;
	//看成树 
	v=v0;
	//树只有一个根节点,其权值为0 
	sum = 0; 
	//首次更新各结点到树的最小权值 
	for(int i = 0;i < maxSize; ++i){
		lowcost[i] = g->edges[v][i];
		vext[i] = 0;				
	}
	//标记结点已经访问
	vext[v] = 1;
	//对其余的n-1个结点进行遍历 
	for(int i = 0;i < maxSize-1; i++){
		//最小值开始取一个极大数 
		int min = INT_MAX;
		//从lowcost数组中的出目前到树最小的结点,如果这个结点已经被访问了即已经被划进树中就不算了
		//负责存储最小值的下标 
		int k;
		for(int j = 0;j < maxSize; ++j){
			if(vext[j] == 0 && lowcost[j] < min){
				min = lowcost[j];
				k = j;
			}
		}
		vext[k] = 1;
		v = k;
		sum += min;
		//更新各结点到树的最小权值 
		for(int i = 0;i < maxSize;i++){
			//如果有某个结点的权值到树的权值更小了,就改变lowcost 
			if(lowcost[i] > g->edges[v][i]){
				lowcost[i] = g->edges[v][i]; 
			}
		}
	} 
} 
int main(int argc, char** argv) {
	MGraph *g;
	create(g,maxSize);
	int sum = 0;
	prim(g,2,sum);
	printf("%d",sum);
	return 0;
}