Add BFS, DSU, and Kosaraju’s algorithm to silver

Add BFS, DSU, and Kosaraju’s algorithm to silver

Aren’t 1 and 2 in gold already? Are you proposing that we move them to silver?

To be honest, I’ve only seen one Silver problem that used DSU.

I haven’t seen a single silver problem that used BFS for Silver. I heard understanding this helps but it’s definitely not required. Likewise for DSU. I’ve seen 3 problems that can use DSU, but DFS also works.

BFS can be used for silver, but not necessary because those can be solved with DFS. DSU can cheese some silver problems, but not necessary because it can be solved with DFS. Kosaraju’s algorithm is not necessary for silver either.