1. knowing that merge sort is usually guranteed (nlogn) but talking about the internal steps of this sort which of the following is a correct answer

2. knowing that topological sorting includes dfs only if you are sure about different answer please explain

1. In the merge step of Merge sort of N elements what is the running time cost of that step?
   1. O(1) b. O(log N) c. O(N) d. O(N log N) e. O(N2)
2. One of the following is used in Topological Sorting:
   1. BFS b. DFS c. Heap d. All of them