In this problem, the input is an undirected graph and an integer k.  If there is a clique of size k, return true.  If there isn't a clique of size k, return false.

A clique is a group of nodes that are connected to eachother by edges.

I found a video about it: https://youtu.be/B801ZELDFZo

The weird thing about this is this variation of the problem is kind of useless.  It's more useful to find the size of the largest clique, but that's not "official" problem for the purpose of NP-completeness.