最短路径 -- Floyd

void Dispath_Floyd(MatGraph g, int A[][MAXV], int path[][MAXV])
{
	int i, j, k, s;
	int apath[MAXV], d; //最短路径（逆向）  &&  顶点个数
	for (i = 0; i < g.n; i++)
		for (j = 0; j < g.n; j++)
		{
			if (A[i][j] != INF && i != j) //i->j存在路径
			{
				cout << "从" << i << "到" << j << "的路径为：";
				k = path[i][j];
				d = 0;  //路径上添加终点 从0开始
				apath[d] = j;
				while (k != -1 && k != i) //添加中间点
				{
					d++;
					apath[d] = k;
					k = path[i][k];
				}
				d++;
				apath[d] = i;  //路径上添加起点
				cout << apath[d];
				for (s = d - 1; s >= 0; s--)
					cout << "," << apath[s];
				cout << "\t路径长度为：" << A[i][j] << endl;
			}
		}
}

void Floyd(MatGraph g)
{
	int A[MAXV][MAXV], path[MAXV][MAXV];
	int i, j, k;
	for (i = 0; i < g.n; i++)
		for (j = 0; j < g.n; j++)
		{
			A[i][j] = g.edges[i][j]; // A记录边权 
			if (i != j && g.edges[i][j] != INF) // path记录k->j的最短(k,...,a,j) 则path(k-1)[k][j]=a
				path[i][j] = i;
			else
				path[i][j] = -1;
		}
	// A表示经由该顶点的最短路径长度，可以为起点，可以为中转点
	for (k = 0; k < g.n; k++)
	{
		for (i = 0; i < g.n; i++)
			for (j = 0; j < g.n; j++)
				if (A[i][j] > A[i][k] + A[k][j]) //修改最短路径
				{
					A[i][j] = A[i][k] + A[k][j];
					path[i][j] = path[k][j];
				}
	}
	Dispath_Floyd(g, A, path);
}