Just a couple of Advent of Code puzzles solved in C. When possible I try to use non obvious ways to solve the puzzle, to make things more creative:
- Day 1 makes use of a simple streaming algorithm to retain top-N max entries.
- Day 2 turns the logic of Rock, Paper, Scissor into a simple equation modulo N.
- Day 3 makes use of bitmaps.
- Day 4 shows abstracting with C structures.
- Day 5 shows linked lists are useful.
- Day 6 will solve in
O(N)instead ofO(N*M). - Day 7 uses recursion and building ad-hoc data structures.
- Day 8 walks data structures using a velocity vector.
- Day 9 has nothing special. Just plain C code to simulate the rope.
- Day 10 Simple but fun. Nothing special. Hints at cycles-exact emulation.
- Day 11 Is an example of how you should not do parsing, assuming tons of stuff about your input. The program uses the LCM to avoid overflow. Yet I had to change int to long, and I did it brutally in
2.c, with vim search and replace. - Day 12 implements the worst queue you'll ever see.
- Day 13 uses a recursive parser that generates nested objects.