[10 marks] A 2-coloring of an undirected graph with n vertices and m edges is the assignment of one of two colors (say, red or green) to each vertex of the graph, so that no two adjacent nodes have the same color. So, if there is an edge (u,v) in the graph, either node u is red and v is green or vice versa. Give an O(n + m) time algorithm (pseudocode!) to 2-colour a graph or determine that no such coloring exists. (Hint: Use BFS) The following shows examples of graphs that are and are not 2-colourable: 2-colourable Not 2-colourable