1 files changed, 56 insertions, 0 deletions

diff --git a/day4/solution.nim b/day4/solution.nim
new file mode 100644
index 0000000..36e90fb
--- /dev/null
+++ b/day4/solution.nim
@@ -0,0 +1,56 @@
+import std/strutils
+import std/sequtils
+
+type
+  # We use begin and length for Range representation to simplify calculations later
+  Range = tuple[begin: int, length: int]
+  Entry = tuple[first: Range, second: Range]
+
+proc part1(entries: seq[Entry]): int =
+  var score = 0
+  for e in entries:
+    var r: Entry
+    # Let first become the leftmost range. In case both ranges start at the same index, we consider the longest one to be first
+    if e.first.begin < e.second.begin or (e.first.begin == e.second.begin and e.first.length >= e.second.length):
+      r.first = e.first
+      r.second = e.second
+    else:
+      r.first = e.second
+      r.second = e.first
+
+    if r.first.length >= r.second.length + r.second.begin - r.first.begin:
+      score += 1
+
+  return score
+
+proc part2(entries: seq[Entry]): int =
+  var score = 0
+  for e in entries:
+    var r: Entry
+    # Let first become the leftmost range. In case both ranges start at the same index, we consider the longest one to be first
+    if e.first.begin < e.second.begin or (e.first.begin == e.second.begin and e.first.length >= e.second.length):
+      r.first = e.first
+      r.second = e.second
+    else:
+      r.first = e.second
+      r.second = e.first
+
+    if r.first.begin + r.first.length - 1 >= r.second.begin:
+      score += 1
+
+  return score
+
+let 
+  content = readFile("./input.txt").strip().splitLines()
+  entries = map(
+    content,
+    proc(line: string): Entry =
+      let tokens = map(line.split({',', '-'}), proc(token: string): int = token.parseInt())
+      (
+        (tokens[0], tokens[1] - tokens[0]+1),
+        (tokens[2], tokens[3] - tokens[2]+1)
+      )
+  )
+
+echo part1(entries)
+echo part2(entries)