You have learned six advanced tree techniques: Euler Tour, Binary Lifting, LCA, Heavy-Light Decomposition, Centroid Decomposition, and Small-to-Large merging. Each solves specific types of problems.
In this section, I'll give you five hard problems. For each, you will decide which technique to use before seeing the solution. This builds pattern recognition, the skill that separates fast solvers from slow ones.
By the end, you will recognize which technique a problem needs by reading the statement.
