プリムアルゴリズム最小生成ツリー

#include "stdio.h"
#include "stdlib.h"
#define MAXINT 32767
#define MAX 100
/*            ，          */
/*
test data: 6 0 1 1 0 2 33 0 3 43 0 4 5 0 5 32 1 2 3 1 3 4 1 4 5 1 5 76 2 3 2 2 4 5 2 5 6 3 4 5 3 5 665 4 5 4 -1 -1 -1
result:
please input node num:
(V0 ,V1)(V1 ,V2)(V2 ,V3)(V0 ,V4)(V4 ,V5)the sum is 15
*/
//        
void read(int a[][MAX],int *v)
{
	int n,i,j,w; 


	printf("please input node num:
");
	scanf("%d",&n);
	if(n>MAX)
	{
		printf("input node value not > %d",MAX);
		return;
	}
	*v=n;
	//   a
	for(i=0;i<n;i++)
		for(j=0;j<n;j++)a[i][j]=MAXINT;
	do
	{
		scanf("%d%d%d",&i,&j,&w);
		if(i==-1||j==-1||w==-1)break;
		a[i][j]=w;
	}while(9);
}
void plmMST(int a[][MAX],int n)
{
	int c,i,j,min_w,min_i,min_j,sum=0;
	//    0     
	a[0][0]=-1;
	for(c=0;c<n-1;c++)
	{
		min_w = MAXINT;
		min_i = -1;
		min_j = -1;

		for(i=0;i<n;i++)
		{
			for(j=0;j<n;j++)
			{
				//     ，   i      (      )    
				if(i!=j&&(a[i][i]==-1&&a[j][j]!=-1||a[i][i]!=-1&&a[j][j]==-1)&&a[i][j]<min_w)
				{
					min_w=a[i][j];
					min_i=i;
					min_j=j;
				}
			}
		}
		//      ，    
		if(min_i!=-1)
		{
			printf("(V%-2d,V%d)",min_i,min_j);
			//a[min_i][min_j]=MAXINT;?
			a[min_i][min_i]=a[min_j][min_j]=-1;
			sum+=min_w;
		}
		else
		{
			printf("      
");
			exit(-2);
		}
	}
	printf("the sum is %d
",sum);

}
void main()
{
	int a[MAX][MAX],vnum;
	read(a,&vnum);
	plmMST(a,vnum);

}