In progressTechnical Screen

Mempool Block Packing and CPFP Phone Screen

CoinbaseSoftware Engineer · Technical Screen · Oct 2026

It was the problem about picking transactions from a mempool to pack into a block. I hadn't really touched this area before, so I was a bit lost when I first read the problem. Part one gives an unsorted array of transactions, each with an id, fee, and size. The block capacity is fixed at 100. You pick some transactions to put in, the total size can't go over, and you want to collect as much fee a…

Shared by a candidate · reported Oct 2026. Interview formats change; use it as a guide, not a script.