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+# Advent of Code 2020 Solutions
+Here's to my first 50 star year since 2017! The goal
+was to make it to top 100 at least once this year,
+and it finally came true on day 22 (and again in day 25
+part 2, but that hardly counts). Honestly,
+I am not at all happy with myself, though.
+
+## Kinds of Solutions
+I "raced" in [Crystal](https://crystal-lang.org), but also tried my hand at
+formal verification in [Coq](https://coq.inria.fr/), and tried out
+an APL dialect called [J](https://jsoftware.com/) for fun.
+I didn't always clean my race day solutions, particularly the ones to the
+"hard" days. I will write about my Coq solutions on [my site](https://danilafe.com).
+
+## Rankings
+Here's the (rather embarassing) table with my times.
+```
+      -------Part 1--------   -------Part 2--------
+Day       Time  Rank  Score       Time  Rank  Score
+ 25   00:07:18   105      0   00:07:24    94      7
+ 24   00:25:27  1496      0   00:43:46  1165      0
+ 23   00:27:30   887      0   01:35:00  1057      0
+ 22   00:03:44    42     59   01:16:52  2242      0
+ 21   00:21:57   612      0   00:26:05   439      0
+ 20   00:27:52   465      0   03:00:50   845      0
+ 19   00:14:56   123      0   00:48:50   439      0
+ 18   00:26:17  1209      0   00:28:01   574      0
+ 17   00:17:23   400      0   00:19:14   281      0
+ 16   00:11:50   627      0   01:03:40  2040      0
+ 15   00:18:11  1772      0   00:30:38  1924      0
+ 14   00:18:05  1220      0   00:39:57  1173      0
+ 13   00:04:59   198      0   01:05:11  1606      0
+ 12   00:06:19   206      0   00:14:17   245      0
+ 11   00:13:23   414      0   00:19:11   261      0
+ 10   00:05:04   293      0   00:31:04  1493      0
+  9   00:08:55  1721      0   00:26:50  3540      0
+  8   00:04:23   275      0   00:09:56   256      0
+  7   00:17:46   832      0   00:24:22   615      0
+  6   00:03:31   385      0   00:09:38   999      0
+  5   00:08:21   839      0   00:27:23  3404      0
+  4   00:07:40   786      0   00:20:26   440      0
+  3   00:02:46   119      0   00:07:40   448      0
+  2   00:03:48   341      0   00:06:01   272      0
+  1   00:07:52  1072      0   00:09:00   748      0
+  ```
+
+## Crystal for Competitive Programming
+I really enjoyed writing Crystal for the Advent of Code, but there were a few reasons
+why it wasn't perfect for the task.
+
+* When you're not banking on brute force speed, you lose some time to the compiler.
+* Numbers are _always_ 32-bit by default, and require constant `_i64` suffixes everywhere
+in the code when they're involved.
+* Type annotations (however necessary they are) for hashes and arrays make refactoring
+a little bit slower.