This is a collection of solutions to the Advent of Code 2019 programming problems implemented in the C programming language. I have done my best to minimize time complexity and running time. This repository only includes solutions to the Intcode problems.
Some of the more complex problems were implemented in a higher-level programming language before being converted to C. The equivalent code is included here as a reference.
These programs are cross-platform, having been tested on Windows and Linux operating systems.
Important: Do not use Windows-style line endings (CR LF, i.e. \r\n).
Only use Unix-style line endings (LF, i.e. \n).
Important: I have tested each program on the example test cases and two
puzzle input files - not a large sample size! I have avoided assumptions about
the input, sometimes even at the cost of performance. However, to avoid memory
allocation, all buffers have fixed sizes. Ensure that all buffers (see #define
statements) have sufficient capacity before running. Not doing so could result
in a stack smashing, segmentation fault, or worse.
I am working within the following constraints to ensure high code quality.
- Adhere to the project style guide.
- Final solutions must be implemented in the C programming language following
the C99 standard.
- Assume signed integer overflow is defined based on two's complement.
- All solutions must be standalone files with no external dependencies beyond
the C standard library (
libc) and the C mathematics library (libm). The first and second problems for a given day must be implemented separately. - Bounds checking is not required for data structures whose capacity is defined by a macro.
- The return values of all C standard library functions must be checked, except
for those returned from the following:
fprintfmemcpyprintf