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。-There are a salesman, I want to n (n < = 10) cities to promote their products. To save travel costs, identify him before departure arbitrary travel expenses between the two cities, want to find a travel route through each city only once, and made travel costs the least.