From 4d07159d1eb9834009c8b02ec50abb631284262a Mon Sep 17 00:00:00 2001
From: j-james
Date: Mon, 12 Dec 2022 03:03:32 -0800
Subject: Day Twelve (Nim)

---
 2022/nim/day12/src/main.nim | 73 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 2022/nim/day12/src/main.nim

diff --git a/2022/nim/day12/src/main.nim b/2022/nim/day12/src/main.nim
new file mode 100644
index 0000000..b6bcc41
--- /dev/null
+++ b/2022/nim/day12/src/main.nim
@@ -0,0 +1,73 @@
+# Day 12: Hill Climbing Algorithm
+import std/[os, strutils, sequtils, sets, terminal]
+
+type Cell = tuple[x: int, y: int]
+
+# slow slow slow
+let input = paramStr(1).readFile().strip().split("\n")
+var grid = input.mapIt(it.toSeq())
+
+proc calc_start(): Cell = # slow
+  for i, line in grid:
+    for j, elevation in line:
+      if elevation == 'S':
+        grid[i][j] = '`'
+        return (i, j)
+
+proc calc_goal(): Cell = # slow
+  for i, line in grid:
+    for j, elevation in line:
+      if elevation == 'E':
+        grid[i][j] = '{' # lol
+        return (i, j)
+
+proc valid(fr, to: Cell, visited: HashSet[Cell], desc: bool): (bool, bool) =
+  if (to.x >= 0) and (to.y >= 0) and (to.x < grid.len) and (to.y < grid[0].len):
+    if to notin visited:
+      let sign = if desc: -1 else: 1
+      if sign * (grid[to.x][to.y].ord - grid[fr.x][fr.y].ord) < 2:
+        if not desc and grid[to.x][to.y] == '{':
+          return (true, true)
+        if desc and grid[to.x][to.y] == 'a':
+          return (true, true)
+        return (true, false)
+  return (false, false)
+
+proc print(cells: HashSet[Cell]) =
+  eraseScreen()
+  for i, line in grid:
+    for j, ele in line:
+      if (i, j) in cells:
+        stdout.write("█")
+      else:
+        stdout.write(ele)
+    stdout.write("\n")
+  sleep(100)
+
+proc search(start: Cell, desc: bool): int =
+  var current = @[start].toHashSet()
+  var visited: HashSet[Cell]
+
+  var steps = 0
+  while true:
+    steps += 1
+    var temp: HashSet[Cell]
+    for c in current:
+      var neighbors: HashSet[Cell]
+      let cells: array[4, Cell] = [(c.x+1, c.y), (c.x-1, c.y), (c.x, c.y+1), (c.x, c.y-1)]
+      for cell in cells:
+        let (valid, success) = valid(c, cell, visited, desc)
+        if success:
+          return steps
+        if valid:
+          neighbors.incl(cell)
+      visited.incl(c)
+      temp.incl(neighbors)
+    current = temp
+    # print(visited)
+
+let start = calc_start()
+let goal = calc_goal()
+
+echo search(start, false)
+echo search(goal, true)
-- 
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