A Dumb Introduction to Z3

5 days ago

The author started exploring constraint solvers, particularly z3, after reading an article on how they relate to LeetCode problems.
Solvers like z3 are tools for solving problems by defining rules and constraints, useful in real-world scenarios such as scheduling and resource allocation.
In z3, terminology includes 'Sort' for types and 'constants' as solver variables, with its own language SMT-LIB2, independent of the host programming language's type system.
A simple equation x + 4 = 7 is solved with z3 in Rust, demonstrating basic usage.
The example of solving linear equations with two variables shows handling of unsatisfiable cases and switching to Real type for solutions.
Multiple solutions are obtained for equations like x^2 = 4 and circle equations, using iterator methods for enumeration.
The coin change problem is tackled with optimization, requiring non-negative constraints and using push/pop for multiple totals.
Sudoku solving is implemented by encoding rules (rows, columns, 3x3 squares) without relying on advanced Sudoku strategies.
A page layout problem arranges boxes without overlap and within page boundaries, showcasing spatial constraint solving.

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