在二分图中求最少的点，让每条边都至少和其中的一个点关联，这就是二分图的“最小顶点覆盖”。二分图的最小顶点覆盖数 =二分图的最大匹配数。-In seeking bipartite graph fewest points, so that each edge and at least one associated point, which is the bipartite graph of the minimum vertex cover. Bipartite graph of the mini