2023 day 11 in Nim

0.08s user 0.01s system 99% cpu 0.094 total

2023/11/day11.nim

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+
+import std/sequtils
+import std/strutils
+import tables
+
+type Point = tuple
+  x: int
+  y: int
+
+type Area* = ref object
+  data: seq[string]
+  x, y: int
+
+proc charAt(a: Area, p: Point): char =
+  a.data[p.x][p.y]
+
+iterator eachPChar(a: Area): (Point, char) =
+  for x in 0..a.x - 1:
+    for y in 0..a.y - 1:
+      let p = (x, y)
+      yield (p, a.charAt(p))
+
+iterator column(a: Area, y: int): char =
+  for x in 0..a.x - 1:
+    yield a.charAt((x, y))
+
+proc realPosition(t: Table[Point, Point], g: Point): Point =
+  let offset = t[g]
+  (g.x + offset.x, g.y + offset.y)
+
+proc solve(a: Area, galaxies: Table[Point, Point], offset: int): int =
+  var galaxies = galaxies
+  let offset = offset - 1
+
+  for x in 0..a.x - 1:
+    if a.data[x].allIt(it == '.'):
+      for pos, off in galaxies:
+        if pos.x > x:
+          galaxies[pos] = (off.x + offset, off.y)
+
+  for y in 0..a.y - 1:
+    if a.column(y).toSeq.allIt(it == '.'):
+      for pos, off in galaxies:
+        if pos.y > y:
+          galaxies[pos] = (off.x, off.y + offset)
+  
+  var distances = initTable[(Point, Point), int]()
+  for g1 in galaxies.keys:
+    for g2 in galaxies.keys:
+      if g1 != g2 and (g1, g2) notin distances and (g2, g1) notin distances:
+        let r1 = realPosition(galaxies, g1)
+        let r2 = realPosition(galaxies, g2)
+        let d = abs(r1.x - r2.x) + abs(r1.y - r2.y)
+        distances[(g1, g2)] = d
+
+  distances.values.toSeq.foldl(a + b)
+
+proc main() =
+  let s = readAll(stdin)
+  var lines = splitLines(s)
+
+  let a = Area(data: lines, x: (len lines) - 1, y: len lines[0])
+
+  var galaxies = initTable[Point, Point]()
+  for p, c in a.eachPChar:
+    if c == '#':
+      galaxies[p] = (0, 0)
+  
+  let p1 = solve(a, galaxies, 2)
+  let p2 = solve(a, galaxies, 1000000)
+
+  echo "Part 1: $1" % [$p1]
+  echo "Part 2: $1" % [$p2]
+
+when isMainModule:
+  main()

2023/11/example

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+...#......
+.......#..
+#.........
+..........
+......#...
+.#........
+.........#
+..........
+.......#..
+#...#.....