Day 11 done

2021/nim/common.nim

@@ -44,15 +44,15 @@ proc doDay*[T](
   expectedPart1: int,
   expectedPart2: int): void =
   time(&"day {day} part 1"): echo day.inputLoader().part1()
-  # time(&"day {day} part 2"): echo day.inputLoader().part2()
+  time(&"day {day} part 2"): echo day.inputLoader().part2()
 
   when not defined(release):
     var p1 = testInput.part1()
     echo p1
     doAssert p1 == expectedPart1
-    # var p2 = testInput.part2()
+    var p2 = testInput.part2()
-    # echo p2
+    echo p2
-    # doAssert p2 == expectedPart2
+    doAssert p2 == expectedPart2
 
 proc reduce*[T, X](s: openArray[T], op: (X, T) -> X, init: X): X =
   result = init

2021/nim/day11.nim

@@ -39,7 +39,45 @@ proc octopi(input: seq[seq[int]]): int =
     for f in allFlashes.items():
       o[f[0]][f[1]] = 0
 
-doDay 11, n => n.loadInput().toGrid(), octopi, octopi,
+proc octopiUntilAll(input: seq[seq[int]]): int =
+  var o = input
+  let h = o.len
+  let w = o[0].len
+  # echo &"w{w} h{h}"
+  for n in 1..1000000:
+    # for nums in o:
+      # echo nums.mapIt($it).join()
+    # echo n
+    var allFlashes = toHashSet[(int, int)] []
+    var flashes = toHashSet[(int, int)] []
+    for y in 0..<h:
+      for x in 0..<w:
+        # inc and check flashes
+        inc o[y][x]
+        if o[y][x] > 9:
+          # echo &"Flash {y}, {x}"
+          inc result
+          flashes.incl (y, x)
+          allFlashes.incl (y, x)
+    while flashes.len > 0:
+      let (y, x) = flashes.pop
+      # echo &"Handling flash {y}, {x}"
+      for p in product @[@[y-1, y, y+1], @[x-1, x, x+1]]:
+        let (fy, fx) = (p[0], p[1])
+        if fx < 0 or fy < 0 or fx >= w or fy >= h or (fx == x and fy == y): continue
+        # inc and check flashes
+        inc o[fy][fx]
+        if o[fy][fx] > 9 and not allFlashes.contains (fy, fx):
+          # echo &"Subflash {fy}, {fx}"
+          inc result
+          flashes.incl (fy, fx)
+          allFlashes.incl (fy, fx)
+    if allFlashes.len() == (w * h):
+      return n
+    for f in allFlashes.items():
+      o[f[0]][f[1]] = 0
+
+doDay 11, n => n.loadInput().toGrid(), octopi, octopiUntilAll,
   @[
     "5483143223",
     "2745854711",
@@ -51,4 +89,4 @@ doDay 11, n => n.loadInput().toGrid(), octopi, octopi,
     "6882881134",
     "4846848554",
     "5283751526",
-    ].toGrid(), 1656, 288957
+    ].toGrid(), 1656, 195