mirror of
https://github.com/Threnklyn/advent-of-code-go.git
synced 2026-05-18 19:13:27 +02:00
alexchao26
79 lines
2.5 KiB
Go
79 lines
2.5 KiB
Go
package main
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import (
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"github.com/alexchao26/advent-of-code-go/util"
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"fmt"
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"strings"
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)
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func main() {
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input := util.ReadFile("../input.txt")
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// split it into a slice of all strings
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inputSliced := strings.Split(input, ",")
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// send the input to a helper function that will return a map {planetName string: planetItOrbits string}
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mapOfOrbits := makeGraphDependencyList(inputSliced)
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sanOrbitsToCom, youOrbitsToCom := recurseToCOM(mapOfOrbits, "SAN"), recurseToCOM(mapOfOrbits, "YOU")
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// need to find where the two run over the same planet...
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// these two variables will store the indexes within the slices, that corresponds to the same planet
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var indexOfYouPlanet, indexOfSanPlanet int
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// iterate through the SAN orbits, nest a loop to search for the same planet in the YOU orbits
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// a map would have better time complexity... due to lookup time
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for indexSan, sanOrbitPlanetString := range sanOrbitsToCom {
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// a boolean to track if the planet was found in the you orbit
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var foundYouPlanet bool
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// iterate through YOU orbits and if the same planet is found, update the indexYou and foundBool
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for indexYou, youOrbitPlanetString := range youOrbitsToCom {
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if youOrbitPlanetString == sanOrbitPlanetString {
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indexOfYouPlanet, foundYouPlanet = indexYou, true
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break
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}
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}
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// if it was found, set the indexOfSanPlanet and stop the looping
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if foundYouPlanet {
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indexOfSanPlanet = indexSan
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break
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}
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}
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// subtract two for the SAN and YOU planets (they're pointers to a planet, not extra orbits to traverse)
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fmt.Println("result is: ", indexOfYouPlanet+indexOfSanPlanet-2)
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}
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func makeGraphDependencyList(inputSlice []string) map[string]string {
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resultMap := make(map[string]string)
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for _, v := range inputSlice {
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slicedPlanets := strings.Split(v, ")")
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inner, outer := slicedPlanets[0], slicedPlanets[1]
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// set the key-value pair on the map/"object"
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resultMap[outer] = inner
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}
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return resultMap
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}
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func recurseToCOM(mapOfOrbits map[string]string, planet string) []string {
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// added to handle part2
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planetsToComSlice := make([]string, 0)
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// start the result at one because triggering this function is using the outerPlanet
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// and needs to include that initial orbit from innerPlanet to outerPlanet
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for {
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planetString, ok := mapOfOrbits[planet]
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if ok {
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// if the planet is found in the map, place the planet on the slice and continue to loop
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planetsToComSlice = append(planetsToComSlice, planet)
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planet = planetString
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} else {
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break
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}
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}
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return planetsToComSlice
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}
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