Skip to content

CodingLevel 3

Graphs and trees

Easy

Medium

Hard

Continue Read the guide View as list

Graph traversal (BFS & DFS)Explore networks systematically, either by diving deep or rippling outward.3 min Advanced graph algorithmsFinding the absolute maximum amount of water you can push through a network of pipes.3 min Shortest paths (Dijkstra & friends)Always take the shortest known path, expanding outward until the destination is reached.3 min Binary trees & traversalHierarchical data branching into at most two children per node.3 min Tries & suffix structuresStore words character-by-character to instantly look up prefixes and autocomplete.3 min Union-Find (DSU)Group elements into sets and instantly check if two items belong to the same group.3 min Binary search trees & balancingFast lookups like an array, fast inserts like a linked list.3 min Topological sortOrdering tasks so that every prerequisite is finished before its dependent task begins.3 min Segment trees & Fenwick treesQuery and update ranges of an array in logarithmic time using a binary tree.3 min Minimum spanning treesConnect every node in a network using the absolute minimum total wire length.3 min Critical path schedulingThe longest chain of dependent tasks sets the floor on how fast everything can finish, speeding up anything else changes nothing.4 min Query predicate evaluatorA WHERE clause is a little tree of yes/no questions, walk it per row, and keep only the rows it answers true.4 min