Prim算法

#define _CRT_SECURE_NO_WARNINGS

/*
	prim朴素实现
	reference: http://www.slyar.com/blog/prim-simplicity-c.html
//*/
#define MAX 100
#define MAXCOST 0x7fffffff

int graph[MAX][MAX];
int mstgraph[MAX][MAX];

int prim(int graph[][MAX], int n)
{
	int lowcost[MAX];
	int mst[MAX];
	int i, j, min, minid, sum = 0;
	
	for (i = 2; i <= n; i++)
	{
		lowcost[i] = graph[1][i];
		mst[i] = 1;
	}
	mst[1] = 0;
	
	for (i = 2; i <= n; i++)
	{
		min = MAXCOST;
		minid = 0;
		for (j = 2; j <= n; j++)
		{
			if (lowcost[j] < min && lowcost[j] != 0)
			{
				min = lowcost[j];
				minid = j;
			}
		}
		printf("V%d ", mst[minid]);
		printf("-V%d", minid);
		printf("=%d\n", min);

		//cout << "V" << mst[minid] << "-V" << minid << "=" << min << endl;
		sum += min;
		lowcost[minid] = 0;
		for (j = 2; j <= n; j++)
		{
			if (graph[minid][j] < lowcost[j])
			{
				lowcost[j] = graph[minid][j];
				mst[j] = minid;
			}
		}
	
	}

	return sum;
}

int main()
{
	int i, j, k, m, n;
	int x, y, cost;
	scanf("%d %d", &m, &n);
	//in >> m >> n;//m=顶点的个数，n=边的个数
	//初始化图G
	for (i = 1; i <= m; i++)
	{
		for (j = 1; j <= m; j++)
		{
			graph[i][j] = MAXCOST;
		}
	}
	//构建图G
	for (k = 1; k <= n; k++)
	{
		scanf("%d %d %d",&x, &y,&cost);
		graph[x][y] = cost;
		graph[y][x] = cost;
	}
	//求解最小生成树
	int Tcost = prim(graph, m);
	//输出最小权值和
	printf("最小权值和=%d\n", Tcost);
	//cout << "" << cost << endl;
	system("pause");
	return 0;
}