(Hard) Constraint Challenge - Various Companies

Good morning!

One of the favorite topics of top companies and startups hiring in design verification is System Verilog constraints. So with that said, here is a difficult problem I came across the other day which has been allegedly asked by companies like Meta and Google.

Question:

Write a constraint where you have a 32 bit value (bit [31:0]) and randomize this value such that every randomization would only allow 2 bits to differ from the previous randomization.

Hint: Do we need to store the previous value somehow or is there an even better way?

Answer: Will be provided in tomorrow’s question of the day post! Have fun and stay curious. 😄