Design a Spreadsheet / Formula Engine

Problem

Design the object model for a spreadsheet with formulas referencing other cells.

Requirements

• setCell(ref, value-or-formula)
• getCell(ref) returns computed value
• recompute dependents on change
• detect circular references

What evaluators look for

• Dependency DAG + topological recompute
• Lazy vs eager evaluation
• Clean separation: parser, graph, evaluator

Extension

Support ranges (SUM(A1:A10)) and discuss how ranges affect the dependency graph.