Every time I see a graph problem in a contest or interview, I can identify that it's a graph problem, but I freeze the moment my first BFS attempt doesn't immediately work.
Does anyone have a mental checklist they run through? Something like: is it weighted, is it directed, do I need shortest path or just reachability, should I think in terms of states instead of nodes?
Would love to hear how more experienced people break the problem down before writing any code.
Sophea K.
Algorithms mentor
My checklist: 1) draw the graph on paper first, 2) ask if it's weighted, 3) ask if you need shortest path, all paths, or just connectivity, 4) only then pick BFS/DFS/Dijkstra. Writing code before answering those three questions is what usually causes the freeze.
Ratanak S.
Community moderator · answered 1h ago
Adding to this — a lot of "graph" problems are secretly state-space search. If the nodes aren't obvious, ask what a "state" is in the problem (position + keys collected, position + time, etc).
Vichet M.
ML practitioner · answered 45m ago
This thread should be pinned forever, genuinely bookmarking it.
Lina C.
Security enthusiast · answered 20m ago