Add day1 problem + solution

day1/day1p2.nim

@@ -0,0 +1,38 @@
+import os
+import sequtils
+import std/strutils
+
+proc main() =
+  let fileName = paramStr(1)
+
+  var increased = 0
+  var lastVal = -1
+
+  var window = [0, 0, 0]
+  var windowPos = 0
+
+  for val in fileName.lines:
+    let intVal = val.parseInt
+    var curVal = 0
+
+    window[windowPos] = intVal
+
+    if windowPos == (len(window) - 1):
+      # add the values and store
+      curVal = window.foldl(a + b)
+
+      if lastVal != -1 and lastVal < curVal:
+        increased += 1
+
+      lastVal = curVal
+
+      # move values up the window
+      window[0] = window[1]
+      window[1] = window[2]
+      window[2] = intVal
+    else:
+      windowPos += 1
+
+  echo increased, " increases"
+
+main()