题目
Prove that the flowing problem that is NP-complete: given an undirected graph G=(V, E) and an integer k, return a clique of size k as well as an independent set of size k, provided both exist.
思路
这道题是要我们证明NP-complete,可以将最大团问题归约到此问题。NP->SAT->3SAT->INDEPENDENT SET->CLIQUE,所以最大团问题是NP-complete问题。在图g中添加k个相互独立的顶点,得到新图g',新加的顶点保证了图g‘存在大小为k的独立集,不影响原图的团,这样即可完成归约。