solution 1

solutions/day01/example.txt

@@ -0,0 +1,6 @@
+3   4
+4   3
+2   5
+1   3
+3   9
+3   3

solutions/day01/solution.nim

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+import std/[strutils, algorithm, sequtils, tables]
+import aoc
+
+proc parseInput(input: string): (seq[int], seq[int]) =
+  for line in input.splitLines():
+    let s = line.splitWhitespace()
+    assert s.len == 2
+    result[0].add parseInt(s[0])
+    result[1].add parseInt(s[1])
+
+proc partOne*(input: string): int =
+  var ids = parseInput(input)
+  ids[0].sort
+  ids[1].sort
+  for (l, r) in zip(ids[0],ids[1]):
+    result += abs(l-r)
+
+
+proc partTwo*(input: string): int =
+  var ids = parseInput(input)
+  let counts = toCountTable ids[1]
+  for id in ids[0]:
+    if id in counts:
+      result += id * counts[id]
+
+solve:
+  "example.txt":
+    partOne: 11
+    partTwo: 31
+  "input.txt":
+    partOne: 1590491
+    partTwo: 22588371