> What is the time complexity of finding the diagonal of a graph
> $G=(\cal V,E)$?
> 
>  - $\cal{O}(|V|^2)$
>  - $\cal{O}(|V|^2+|V| \cdot |E|)$
>  - $\cal{O}(|V|^2\cdot |E|)$
>  - $\cal{O}(|V|\cdot |E|^2)$


<sup>The diagonal of a graph $G$ is the longest distance in graph. </sup>

I have no idea what to do about it, I need a complete analysis on how to solve a problem like this.