Onsite

Tree Sums, a Retry HOF, and a Rental Watchlist Design Question

AirbnbSoftware Engineer · Onsite · Sep 2025

The interview was on the easier side. The algorithm question was about a tree, where the leaves are numbers and each parent node's value equals the sum of its children. You need to be able to get the value of any given node. The second part adds a mutation: you can turn a node into a leaf, or take a leaf and attach a subtree to it, turning it into a parent node. Again, you need to be able to get…

Shared by a candidate · reported Sep 2025. Interview formats change; use it as a guide, not a script.