How to check if an undirected graph has an odd length cycle?

Your approach is the right one. You can't do better than that The reason that works is that if you label the vertices by their depth while doing BFS, then all edges connect either same labels or labels that differ by one. It's clear that if there is an edge connecting the same labels then there is an odd cycle.

If not then we can color all odd labels white and all even labels black.

Your approach is the right one. You can't do better than that. The reason that works is that if you label the vertices by their depth while doing BFS, then all edges connect either same labels or labels that differ by one.It's clear that if there is an edge connecting the same labels then there is an odd cycle.

If not then we can color all odd labels white and all even labels black.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.