Add day11 problem + solution

day11/p2.nim

@@ -0,0 +1,58 @@
+import os, sets
+import std/[strutils, sequtils]
+
+proc increaseEnergy(octopi: var seq[seq[uint8]], flashedOctopi: var HashSet[(int, int)], i, j: int) =
+
+  var stack: seq[(int, int)] = @[(i, j)]
+
+  while stack.len > 0:
+    let (i, j) = stack.pop
+
+    if i < 0 or i >= len(octopi) or
+      j < 0 or j >= len(octopi[i]) or
+      (i, j) in flashedOctopi:
+      continue
+
+    if octopi[i][j] < 9:
+      octopi[i][j] += 1
+    else:
+      flashedOctopi.incl((i, j))
+      octopi[i][j] = 0
+
+      let energyIncreases = [
+        (i-1, j-1), (i-1, j), (i-1, j+1),
+        (i, j-1),             (i, j+1),
+        (i+1, j-1), (i+1, j), (i+1, j+1),
+      ]
+
+      stack.add energyIncreases
+
+
+proc main() =
+  let fileName = paramStr(1)
+
+  var octopi: seq[seq[uint8]]
+
+  for line in fileName.lines:
+    octopi.add line.mapIt((ord(it) - ord('0')).uint8)
+
+  var step = 0
+  while true:
+    var flashedOctopi: HashSet[(int, int)]
+
+    for i in 0 ..< len(octopi):
+      for j in 0 ..< len(octopi[0]):
+        octopi.increaseEnergy(flashedOctopi, i, j)
+
+    step += 1
+
+    # check for all zeroes
+    if octopi.allIt(it.allIt(it == 0)):
+      break
+
+  for octoLine in octopi:
+    echo octoLine.join("")
+
+  echo "Steps to sync: ", step
+
+main()