This question evaluates C++ container and iterator design, low-level language proficiency, algorithmic reasoning for redistributing numeric values, and the ability to produce thorough tests for correctness and edge cases.
Implement std::flat_map in C++, including its iterator; explain design choices and add thorough test cases. Given an array of integers representing individual wealth (negative, zero, or positive), redistribute the wealth so that every person’s wealth is as close as possible; describe your approach aloud while coding.