Worked on the valhalla/valhalla repository to implement deterministic tile generation, addressing the challenge of nondeterministic outputs in map data processing. The solution involved sorting tweeners within bins by GraphId using a custom comparator, graphid_less, ensuring that tile creation is reproducible across different runs. This approach aids debugging, improves caching efficiency, and enhances the reliability of continuous integration pipelines. The work leveraged C++ and applied knowledge of data structures and graph algorithms to achieve consistent ordering. By focusing on determinism, the changes simplified regression testing and contributed to more predictable software behavior in the tile generation workflow.