## Editorial for DMOPC '18 Contest 6 P3 - Wish Upon a Star

Remember to use this editorial only when stuck, and not to copy-paste code from it. Please be respectful to the problem author and editorialist.

Submitting an official solution before solving the problem yourself is a bannable offence.

Authors: Kirito

For of points, we can add each edge, and see if it forms a cycle (namely, it connects two already connected nodes). We count the number of such edges, and output YES if there is at most 1 such edge, and NO otherwise.

Time Complexity:

Let denote the number of connected components. This can be computed in using DFS.

For of points, we observe that the answer is always yes if or . The first case gives us a forest, and the second case forms a forest with a single extra edge.

Time Complexity: