2023 Day 11 Part 1

2023/day11.nim

@@ -0,0 +1,69 @@
+import std/algorithm
+import std/deques
+import std/enumerate
+import std/math
+import std/sequtils
+import std/sets
+import std/strscans
+import std/strutils
+import std/sugar
+import std/tables
+
+proc dbg[T](v: T): T = (echo(v); v)
+
+type Point = tuple
+  r: int
+  c: int
+
+type Universe = object
+  rows: int
+  cols: int
+  grid: Table[Point, char]
+  galaxies: seq[Point]
+
+func parseUniverse(text: string): Universe =
+  let lines = text.strip.splitLines()
+  result.rows = lines.len
+  result.cols = lines[0].len
+
+  for (r, line) in enumerate(lines):
+    for (c, sym) in enumerate(line):
+      result.grid[(r, c)] = sym
+
+      if sym == '#':
+        result.galaxies.add (r, c)
+
+func expandRows(rows: seq[string]): seq[string] =
+  for (r, row) in enumerate(rows):
+    result.add(row)
+    if '#' notin row:
+      result.add(row)
+
+func transpose(rows: seq[string]): seq[string] =
+  for c in 0 ..< rows[0].len:
+    var col = ""
+    for r in 0 ..< rows.len:
+      col = col & rows[r][c]
+    result.add col
+
+func expand(text: string): string =
+  let rows = text.strip.splitlines
+  let e1 = rows.expandRows
+
+  let cols = e1.transpose
+  let e2 = cols.expandRows
+
+  e2.transpose.join("\n")
+
+func manhattan(a: Point, b: Point): int =
+  abs(a.r - b.r) + abs(a.c - b.c)
+
+proc part1(): int =
+  let text = readFile("input/day11.txt")
+  let u = parseUniverse(expand(text))
+
+  for (i, a) in enumerate(u.galaxies):
+    for b in u.galaxies[i..^1]:
+      result.inc manhattan(a, b)
+
+echo part1()