60 lines
1.6 KiB
Go
60 lines
1.6 KiB
Go
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package main
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import (
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"log"
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"os"
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"strings"
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"github.com/thoas/go-funk"
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)
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func main() {
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inputBytes, _ := os.ReadFile("input.txt")
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input := strings.Split(string(inputBytes), "\n")
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log.Println("Puzzle 1:", puzzle1(input))
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log.Println("Puzzle 2:", puzzle2(input))
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}
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func puzzle1(input []string) int {
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return do(input, false)
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}
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func puzzle2(input []string) int {
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return do(input, true)
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}
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func do(input []string, puzzle2 bool) int {
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connections := map[string][]string{}
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// Read input
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for _, line := range input {
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split := strings.Split(line, "-")
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connections[split[0]] = append(connections[split[0]], split[1])
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connections[split[1]] = append(connections[split[1]], split[0])
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}
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// Find all routes from start to end
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return len(route(puzzle2, connections, []string{"start"}, false))
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}
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func route(puzzle2 bool, connections map[string][]string, visited []string, smallTwice bool) (routes [][]string) {
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// Find all routes from last visited to end
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for _, next := range connections[visited[len(visited)-1]] {
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// Check if next is end
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if next == "end" {
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routes = append(routes, append(visited, next))
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continue
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}
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// Can visit a single small cave twice, but all remaining caves once
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if next[0] >= 'a' && next[0] <= 'z' && funk.ContainsString(visited, next) {
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if next != "start" && puzzle2 && !smallTwice {
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routes = append(routes, route(puzzle2, connections, append(visited, next), true)...)
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}
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continue
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}
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// Check next possible routes
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routes = append(routes, route(puzzle2, connections, append(visited, next), smallTwice)...)
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}
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// Return all found routes
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return routes
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}
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