Interview Question 15: Create a compact data structure

A tree based data structure of distribution of post offices in a county is shown above. 
- How do you store this data structure efficiently in a memory?
- Create a hardware (algorithm based) to find out whether given post office exists. For example if input to design is PO21 the module should traverse the data structure and show whether it exists or not.

Interview Question 14: Continuous Memory Read Writes

This is a high performance design question. Create a block which is an event counter as shown below. 

This module is implemented using a single port memory as it has large number (millions) of counters. Every clock a valid signal indicates an increment or decrement operation of a counter indicated by an address. This block also produces output of the selected counter after a fixed latency.

Essentially you need to design a “Read-Modify-Write” operation. Assume that the chosen memory requires 2 clocks to complete the write and 2 clocks to read the data. The command and address combination can happen in any sequence. For example you may receive increment/decrement command for the same address on 10 consecutive clock cycles.