112 lines
2.2 KiB
Go
112 lines
2.2 KiB
Go
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package main
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import (
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"AoC2020/helper"
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"fmt"
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"os"
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"regexp"
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"strconv"
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"strings"
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)
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var lineBreak = "\n"
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type tile struct {
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neighbourID [4]int
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edges [4]string
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}
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func main() {
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args := os.Args[1:]
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input, err := helper.GetFile(args[0])
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if err != nil {
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fmt.Println(err)
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}
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tileInput := strings.Split(input, lineBreak+lineBreak)
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fmt.Println(len(tileInput))
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tiles := getTiles(tileInput)
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corners := findCorners(tiles)
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fmt.Println(corners)
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product := corners[0]
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for _,val := range corners[1:]{
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product *= val
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}
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fmt.Println(product)
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}
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func getTiles(input []string) map[int][4]string{
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var tiles = make(map[int][4]string)
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for _, val := range input {
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id, edges := getTile(val)
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fmt.Printf("ID:%v \n",id )
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tiles[id] = edges
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}
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return tiles
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}
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func getTile(input string) (int, [4]string) {
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tilesRow := strings.Split(input, lineBreak)
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var edges [4]string
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edges[0] = tilesRow[1]
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edges[2] = tilesRow[len(tilesRow)-1]
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for _, val := range tilesRow[1:] {
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edges[3] = edges[3]+val[0:1]
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edges[1] = edges[1]+val[len(val)-1:]
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}
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r, _ := regexp.Compile("[0-9]{4}")
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number, _ := strconv.Atoi(r.FindString(tilesRow[0]))
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return number, edges
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}
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func getAllEdges(tiles map[int][4]string, id int) []string{
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var edges []string
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for key,val := range tiles {
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if key != id {
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for _, edge := range val {
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edges = append(edges, edge)
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edges = append(edges, reverse(edge))
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}
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}
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}
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return edges
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}
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func findCorners(tiles map[int][4]string) []int{
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var cornerIds []int
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for key,val := range tiles{
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edgesOfOtherTiles := getAllEdges(tiles,key)
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fmt.Printf("ID: %v, MatchingEdges: %v \n",key,countMatchingEges(edgesOfOtherTiles,val))
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if countMatchingEges(edgesOfOtherTiles,val) <= 2{
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cornerIds= append(cornerIds,key)
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}
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}
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return cornerIds
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}
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func countMatchingEges(allEdges []string, tileEdges [4]string) int{
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count := 0
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for _, val := range tileEdges{
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if hasMatchingEdge(allEdges,val){
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count ++
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}
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}
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return count
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}
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func hasMatchingEdge(edges []string, edge string) bool {
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for _, val := range edges {
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if val == edge{
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return true
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}
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}
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return false
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}
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func reverse(s string) string {
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runes := []rune(s)
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for i, j := 0, len(runes)-1; i < j; i, j = i+1, j-1 {
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runes[i], runes[j] = runes[j], runes[i]
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}
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return string(runes)
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}
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