Squares. Design and analyze an algorithm that takes as input an undirected graph $G=(V,E)$ and determines whether $G$ contains a simple cycle $($that is$,$ a cycle which doesn't intersect itself$)$ of length four. Its running time should be at most $O(|V{|}^3).$

You may assume that the input graph is represented either as an adjacency matrix or with adjacency lists, whichever makes your algorithm simpler.