We said that BFS and DFS run in linear time. We did not say which of our two representations, adjacency lists and adjacency matrices, was chosen.

We said that BFS and DFS run in linear time. We did not say which of our two representations, adjacency lists and adjacency matrices, was chosen.

Both representations are possible, and will yield linear time.

From these two representations, exactly the adjacency matrices guarantee linear time.

From these two representations, exactly the adjacency lists guarantee linear time.