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main.go
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main.go
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package main
import (
"fmt"
"github.com/jyggen/advent-of-go/internal/solver"
"github.com/jyggen/advent-of-go/internal/utils"
"os"
"strconv"
)
func main() {
p1, p2, err := solver.SolveFromFile(os.Stdin, SolvePart1, SolvePart2)
if err != nil {
panic(err)
}
fmt.Println(p1)
fmt.Println(p2)
}
type cave struct {
name string
small bool
}
type item struct {
name string
duplicatedSmall bool
available []string
}
func parseInput(input string) map[string][]cave {
remaining := utils.ToStringSlice(input, "\n")
connections := make(map[string][]cave, len(remaining))
for _, r := range remaining {
parts := utils.ToStringSlice(r, "-")
for _, v := range [2][2]string{
{parts[0], parts[1]},
{parts[1], parts[0]},
} {
p1 := cave{name: v[1], small: false}
if v[1] != "start" && v[1] != "end" && !utils.IsUpper(v[1]) {
p1.small = true
}
if _, ok := connections[v[0]]; !ok {
connections[v[0]] = make([]cave, 0, len(connections))
}
connections[v[0]] = append(connections[v[0]], p1)
}
}
return connections
}
func traverse(connections map[string][]cave, i item, allowDuplicates bool) int {
if i.name == "end" {
return 1
}
paths := 0
for _, o := range connections[i.name] {
if o.name == "start" {
continue
}
duplicated := i.duplicatedSmall
a := make([]string, len(i.available))
copy(a, i.available)
if o.small {
visited := true
for k, v := range a {
if v == o.name {
a = append(a[:k], a[k+1:]...)
visited = false
break
}
}
if visited {
if duplicated || !allowDuplicates {
continue
} else {
duplicated = true
}
}
}
paths += traverse(connections, item{
name: o.name,
duplicatedSmall: duplicated,
available: a,
}, allowDuplicates)
}
return paths
}
func SolvePart1(input string) (string, error) {
connections := parseInput(input)
available := make([]string, 0, len(connections))
for k := range connections {
if k != "start" && k != "end" && !utils.IsUpper(k) {
available = append(available, k)
}
}
paths := traverse(connections, item{
name: "start",
duplicatedSmall: false,
available: available,
}, false)
return strconv.Itoa(paths), nil
}
func SolvePart2(input string) (string, error) {
connections := parseInput(input)
available := make([]string, 0, len(connections))
for k := range connections {
if k != "start" && k != "end" && !utils.IsUpper(k) {
available = append(available, k)
}
}
paths := traverse(connections, item{
name: "start",
duplicatedSmall: false,
available: available,
}, true)
return strconv.Itoa(paths), nil
}