Advent of Code 2017

My solutions for AoC 2017. I did not aim to compete on the leaderboards (i.e. my solutions tend to be a lot more verbose than what you would write when trying to finish as quickly as possible), I simply used this as an opportunity to write some (modern) C++ again.

Prerequisites

• CMake (3.8 or newer should work)
• Compiler supporting C++17 (I used GCC 7.2 myself and also tested with Visual Studio 2017).
• All code is solely based on the STL, no additional libraries needed.

Overview

The program expects the input files to be available as inputs/Day{01-25}.txt relative to the location of the executable. The CMake install target will place the executable in the root folder of the repository (running it from there will work out of the box). If you're running the program from somewhere else (Visual Studio solution for example), you'll have to copy the "inputs" folder to the appropriate location.

Command Line Options:

• Running the executable without any arguments will simply execute all solutions.
• 1 to 25 can be used as command line arguments to only execute the solution(s) of the respective day(s).
• The argument b can be used to run a small 'benchmark'. This will execute each solution 100 times and determine minimum, maximum, and average run time.

Benchmark Results

When running the benchmark function on my machine (Intel i7-7500U @ 2.7GHz, Windows 10 64-bit), I got the following results:

+----------+---------------+---------------+---------------+
| Solution | Min Time (ms) | Avg Time (ms) | Max Time (ms) |
+----------+---------------+---------------+---------------+
|  Day01   |       0.00000 |       0.00000 |       0.00000 |
|  Day02   |       0.00000 |       0.15628 |      15.62760 |
|  Day03   |       0.00000 |       0.00000 |       0.00000 |
|  Day04   |       0.00000 |       1.87573 |      15.69390 |
|  Day05   |      62.45930 |      72.81952 |      78.18150 |
|  Day06   |       0.00000 |       3.28161 |      15.66570 |
|  Day07   |       0.00000 |       1.71826 |      15.62900 |
|  Day08   |       0.00000 |       0.93794 |      15.66080 |
|  Day09   |       0.00000 |       0.31219 |      15.61490 |
|  Day10   |       0.00000 |       0.15632 |      15.63180 |
|  Day11   |       0.00000 |       0.46873 |      15.62730 |
|  Day12   |       0.00000 |       2.50027 |      15.63190 |
|  Day13   |      15.58430 |      26.87823 |      31.29580 |
|  Day14   |       0.00000 |       7.65717 |      15.68930 |
|  Day15   |     296.85920 |     314.57023 |     328.20760 |
|  Day16   |      15.59310 |      24.69076 |      31.29510 |
|  Day17   |     421.91730 |     428.48279 |     453.17420 |
|  Day18   |       0.00000 |       2.34440 |      15.67140 |
|  Day19   |       0.00000 |       0.62470 |      15.62830 |
|  Day20   |      78.06510 |      78.60206 |      93.76080 |
|  Day21   |      93.72020 |     101.88577 |     109.42580 |
|  Day22   |     281.20980 |     284.24885 |     312.53520 |
|  Day23   |      78.09190 |      87.04042 |      93.80140 |
|  Day24   |     124.96810 |     136.88948 |     140.70860 |
|  Day25   |       0.00000 |      14.68867 |      15.69710 |
+----------+---------------+---------------+---------------+

This was when compiling with GCC v7.2 (-O3 -march=native).

With Visual Studio 2017 I got the following results (worse run times across the board):

+----------+---------------+---------------+---------------+
| Solution | Min Time (ms) | Avg Time (ms) | Max Time (ms) |
+----------+---------------+---------------+---------------+
|  Day01   |       0.04549 |       0.04961 |       0.10261 |
|  Day02   |       0.19041 |       0.19748 |       0.27998 |
|  Day03   |       0.02010 |       0.02240 |       0.03773 |
|  Day04   |       2.66614 |       2.76332 |       3.71235 |
|  Day05   |     135.06879 |     135.44820 |     137.94192 |
|  Day06   |       4.11045 |       4.28127 |       4.68628 |
|  Day07   |       2.72925 |       2.80057 |       3.32130 |
|  Day08   |       2.35372 |       2.39939 |       2.62276 |
|  Day09   |       1.64178 |       1.68478 |       2.47678 |
|  Day10   |       0.11742 |       0.13666 |       0.21862 |
|  Day11   |       0.56419 |       0.59471 |       0.75354 |
|  Day12   |       3.77582 |       3.89276 |       5.49060 |
|  Day13   |      31.23091 |      32.45589 |      33.03455 |
|  Day14   |       7.30728 |       7.56851 |      10.66207 |
|  Day15   |    1177.58838 |    1187.67891 |    1201.74299 |
|  Day16   |      40.54493 |      40.99844 |      42.49103 |
|  Day17   |     427.00692 |     428.06277 |     431.79581 |
|  Day18   |       1.83502 |       1.90281 |       2.15378 |
|  Day19   |       0.45417 |       0.46845 |       0.60403 |
|  Day20   |      95.03903 |      95.52701 |      97.40932 |
|  Day21   |     246.97525 |     248.19577 |     250.69360 |
|  Day22   |     423.09111 |     426.62988 |     460.46708 |
|  Day23   |      72.14081 |      72.61846 |      75.22197 |
|  Day24   |     155.45110 |     155.88400 |     158.97445 |
|  Day25   |      56.45007 |      56.69644 |      57.29106 |
+----------+---------------+---------------+---------------+

Missing / Alternative Solutions

Day 3

Initially I wrote a small C program for part 1. I did not bother to make a C++ version of this (it's trivial once you figure out that you can simply count up from the bottom right square).

Day 4

I wrote a solution for both parts in C++. But my first solution of part 1 was this bash one-liner:

sed -re "/\<(\w+)\>.*\<\1\>/d" input.txt | wc -l

Day 7 (Part 1)

I did not write any code for part 1. I solved it just by searching in my text editor. The following key sequence (vim) will most likely solve the part 1 for most input files of this day:

qq0*q100@q