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Build a spreadsheet with formulas

HardP2Build

Build a spreadsheet with formulas in React: a cell grid where cells can contain values or formulas that refer to other cells.

Time box: 90 to 120 minutes. Parsing a small set of formulas is enough.

Requirements

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A grid with column letters (A, B, ..., Z) and row numbers; cells hold raw input and display the computed value
Input starting with = is a formula: arithmetic with + - * /, parentheses, numbers, A1-style cell references and SUM(A1:A5) over ranges
Referenced cells are resolved recursively, and changing a cell recomputes all cells that depend on it, directly or indirectly, but not unrelated ones
A dependency graph (precedents and dependents per cell) is maintained and updated when a formula is edited
Circular references (for example A1 = B1 and B1 = A1) are detected and the affected cells show #CYCLE!; division by zero shows #DIV/0! and other invalid input shows #ERROR!
Editing shows the raw formula, and the display shows the evaluated value; the formula bar reflects the active cell

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