有一推销员，欲到n(n<=10) 个城市推销产品。为了节省旅行费用，在出发前他查清了任意两个城市间的旅行费用，想找到一条旅行路线，仅经过每个城市一次，且使旅行费用最少。本问题已知城市n，和n*n的表达任意两个城市间费用的矩阵。试求最短路径及其费用；-A salesman, wants to n (n < = 10) cities to promote their products. To save travel costs, find out before his departure,