advent-of-code/2021/nim/day12.nim
2021-12-13 11:46:55 -06:00

44 lines
1.2 KiB
Nim

import ./common, std/[sequtils, algorithm, sugar, sets, strformat, strutils, tables]
proc visit(curNode: string, graph: Table[string, HashSet[string]], visitedNodes: HashSet[string]): int =
if curNode == "end": return 1
let nv = if curNode == curNode.toUpper(): visitedNodes else: visitedNodes + [curNode].toHashSet
let toVisit = (graph[curNode] - nv)
if toVisit.len() == 0: return 0
for node in toVisit: result += visit(node, graph, nv)
proc pathing(input: seq[string]): int =
var graph: Table[string, HashSet[string]] = initTable[string, HashSet[string]]()
for l in input:
let nodes = l.split("-")
if graph.hasKey(nodes[0]): graph[nodes[0]].incl(nodes[1])
else: graph[nodes[0]] = toHashSet([nodes[1]])
if graph.hasKey(nodes[1]): graph[nodes[1]].incl(nodes[0])
else: graph[nodes[1]] = toHashSet([nodes[0]])
visit("start", graph, toHashSet[string]([]))
proc part2(input: seq[string]): int =
result = 0
doDay 12, n => n.loadInput, pathing, part2,
@[
"fs-end",
"he-DX",
"fs-he",
"start-DX",
"pj-DX",
"end-zg",
"zg-sl",
"zg-pj",
"pj-he",
"RW-he",
"fs-DX",
"pj-RW",
"zg-RW",
"start-pj",
"he-WI",
"zg-he",
"pj-fs",
"start-RW",
], 226, 0