一种算法，用于找到集盖问题的最小尺寸集盖

In the Set Covering problem, we are given a universe U, such that |U|=n, and sets S1,……,Sk are subsets of U. A set cover is a collection C of some of the sets from S1,……,Sk whose union is the entire universe U. In the Set Covering problem, we are given a uni