Graphs

Count connected components of land cells in a 2D grid

Fill connected pixels in an image with a replacement color

Find the largest connected land area in a binary grid

Deep clone an undirected graph given a start node

Determine whether a path exists between two vertices

Check whether all rooms are reachable starting from room 0

Count connected components in an adjacency matrix

Determine if all courses can be finished with prerequisites

Return a valid course order when possible

Find minutes until all fresh oranges rot

Find time for all nodes to receive signal from source

Find cheapest cost with at most K stops

Find all words in a board using trie-guided DFS