This original problem is titled ‘My Ancestor’ and was used in the Thailand ICPC National Contest 2009. Abridged problem description: Given a weighted (family) tree of up to N ≤ 80K vertices with a special trait: Vertex values are increasing from root to leaves. Find the ancestor vertex closest to the root from a starting vertex v that has weight at least P. There are up to Q ≤ 20K such offline queries.

I am also unable to find the actual link of the problem and hence the solution. Actually this problem is given in steven and felix book.