2023 Day 1

2023/day01.nim

@@ -0,0 +1,58 @@
+const numbers = "0123456789"
+const words = @[
+  "one",
+  "two",
+  "three",
+  "four",
+  "five",
+  "six",
+  "seven",
+  "eight",
+  "nine",
+]
+
+proc part1(): int =
+  let f = open("input/day01.txt")
+  defer: f.close()
+
+  var line: string
+  while f.readLine(line):
+    var nums: seq[int] = @[]
+    for char in line:
+      if char in numbers:
+        nums.add(char.int - '0'.int)
+
+    result += 10 * nums[0] + nums[^1]
+
+proc extractNumsOverlap(line: string): seq[int] =
+  var i = 0
+  while i < line.len:
+    let char = line[i]
+
+    if char in numbers:
+      result.add(char.int - '0'.int)
+      inc i
+      continue
+
+    for n, word in words:
+      let
+        size = word.len
+        cap = min(i + size, line.len)
+      if line[i..<cap] == word:
+        result.add(n+1)
+        break
+    inc i
+
+proc part2(): int =
+  let f = open("input/day01.txt")
+  defer: f.close()
+
+  var line: string
+  while f.readLine(line):
+    let
+      nums = extractNumsOverlap(line)
+
+    result += 10 * nums[0] + nums[^1]
+
+echo part1()
+echo part2()