day09

day09/day09.go

@@ -0,0 +1,94 @@
+package day09
+
+import (
+	"aoc2015/aoclib"
+	"math"
+	"strconv"
+	"strings"
+)
+
+func getDistanceMap(input []string) ([]string, map[string]map[string]int) {
+	distances := make(map[string]map[string]int)
+	var retCities []string
+
+	for _, line := range input {
+		distDescr := strings.Split(line, " = ")
+		cities := strings.Split(distDescr[0], " to ")
+		distance, _ := strconv.Atoi(distDescr[1])
+
+		if _, ok := distances[cities[0]]; !ok {
+			distances[cities[0]] = make(map[string]int)
+			retCities = append(retCities, cities[0])
+		}
+		distances[cities[0]][cities[1]] = distance
+		if _, ok := distances[cities[1]]; !ok {
+			distances[cities[1]] = make(map[string]int)
+			retCities = append(retCities, cities[1])
+		}
+		distances[cities[1]][cities[0]] = distance
+	}
+
+	return retCities, distances
+}
+
+func cityPermutations(slice []string) (permutations [][]string) {
+	if len(slice) == 1 {
+		return [][]string{slice}
+	} else if len(slice) == 2 {
+		return [][]string{
+			{
+				slice[0],
+				slice[1],
+			},
+			{
+				slice[1],
+				slice[0],
+			},
+		}
+	} else {
+		for i := range slice {
+			newSlice := make([]string, i)
+			copy(newSlice, slice[:i])
+			newSlice = append(newSlice, slice[i+1:]...)
+			subPermutations := cityPermutations(newSlice)
+			for _, subPermutation := range subPermutations {
+				permutations = append(permutations, append([]string{slice[i]}, subPermutation...))
+			}
+		}
+		return permutations
+	}
+}
+
+func getMinMaxDistances(permutations [][]string, distances map[string]map[string]int) (int, int) {
+	minDistance := math.MaxInt32
+	maxDistance := 0
+
+	for _, v := range permutations {
+		thisDistance := 0
+		for i := 0; i < len(v)-1; i++ {
+			thisDistance += distances[v[i]][v[i+1]]
+		}
+		if thisDistance < minDistance {
+			minDistance = thisDistance
+		}
+		if thisDistance > maxDistance {
+			maxDistance = thisDistance
+		}
+	}
+
+	return minDistance, maxDistance
+}
+
+func Part1(puzzle aoclib.Puzzle) interface{} {
+	cities, distances := getDistanceMap(puzzle.GetInputArray())
+	minDistance, _ := getMinMaxDistances(cityPermutations(cities), distances)
+
+	return minDistance
+}
+
+func Part2(puzzle aoclib.Puzzle) interface{} {
+	cities, distances := getDistanceMap(puzzle.GetInputArray())
+	_, maxDistance := getMinMaxDistances(cityPermutations(cities), distances)
+
+	return maxDistance
+}

inputs/9

@@ -0,0 +1,28 @@
+Faerun to Tristram = 65
+Faerun to Tambi = 129
+Faerun to Norrath = 144
+Faerun to Snowdin = 71
+Faerun to Straylight = 137
+Faerun to AlphaCentauri = 3
+Faerun to Arbre = 149
+Tristram to Tambi = 63
+Tristram to Norrath = 4
+Tristram to Snowdin = 105
+Tristram to Straylight = 125
+Tristram to AlphaCentauri = 55
+Tristram to Arbre = 14
+Tambi to Norrath = 68
+Tambi to Snowdin = 52
+Tambi to Straylight = 65
+Tambi to AlphaCentauri = 22
+Tambi to Arbre = 143
+Norrath to Snowdin = 8
+Norrath to Straylight = 23
+Norrath to AlphaCentauri = 136
+Norrath to Arbre = 115
+Snowdin to Straylight = 101
+Snowdin to AlphaCentauri = 84
+Snowdin to Arbre = 96
+Straylight to AlphaCentauri = 107
+Straylight to Arbre = 14
+AlphaCentauri to Arbre = 46

inputs/9_test

@@ -0,0 +1,3 @@
+London to Dublin = 464
+London to Belfast = 518
+Dublin to Belfast = 141

main.go

@@ -10,6 +10,7 @@ import (
 	"aoc2015/day06"
 	"aoc2015/day07"
 	"aoc2015/day08"
+	"aoc2015/day09"
 	"flag"
 	"fmt"
 	"os"
@@ -25,31 +26,34 @@ var timeitNumber int
 var myDir, _ = filepath.Abs(filepath.Dir(os.Args[0]))
 
 func initDayFunctions() {
-	dayFunctions = make(map[int]map[int]func(puzzle aoclib.Puzzle) interface{})
-	dayFunctions[1] = make(map[int]func(puzzle aoclib.Puzzle) interface{})
+	dayFunctions = make(map[int]map[int]func(puzzle aoclib.Puzzle) interface{}, 25)
+	dayFunctions[1] = make(map[int]func(puzzle aoclib.Puzzle) interface{}, 2)
 	dayFunctions[1][1] = day01.Part1
 	dayFunctions[1][2] = day01.Part2
-	dayFunctions[2] = make(map[int]func(puzzle aoclib.Puzzle) interface{})
+	dayFunctions[2] = make(map[int]func(puzzle aoclib.Puzzle) interface{}, 2)
 	dayFunctions[2][1] = day02.Part1
 	dayFunctions[2][2] = day02.Part2
-	dayFunctions[3] = make(map[int]func(puzzle aoclib.Puzzle) interface{})
+	dayFunctions[3] = make(map[int]func(puzzle aoclib.Puzzle) interface{}, 2)
 	dayFunctions[3][1] = day03.Part1
 	dayFunctions[3][2] = day03.Part2
-	dayFunctions[4] = make(map[int]func(puzzle aoclib.Puzzle) interface{})
+	dayFunctions[4] = make(map[int]func(puzzle aoclib.Puzzle) interface{}, 2)
 	dayFunctions[4][1] = day04.Part1
 	dayFunctions[4][2] = day04.Part2
-	dayFunctions[5] = make(map[int]func(puzzle aoclib.Puzzle) interface{})
+	dayFunctions[5] = make(map[int]func(puzzle aoclib.Puzzle) interface{}, 2)
 	dayFunctions[5][1] = day05.Part1
 	dayFunctions[5][2] = day05.Part2
-	dayFunctions[6] = make(map[int]func(puzzle aoclib.Puzzle) interface{})
+	dayFunctions[6] = make(map[int]func(puzzle aoclib.Puzzle) interface{}, 2)
 	dayFunctions[6][1] = day06.Part1
 	dayFunctions[6][2] = day06.Part2
-	dayFunctions[7] = make(map[int]func(puzzle aoclib.Puzzle) interface{})
+	dayFunctions[7] = make(map[int]func(puzzle aoclib.Puzzle) interface{}, 2)
 	dayFunctions[7][1] = day07.Part1
 	dayFunctions[7][2] = day07.Part2
-	dayFunctions[8] = make(map[int]func(puzzle aoclib.Puzzle) interface{})
+	dayFunctions[8] = make(map[int]func(puzzle aoclib.Puzzle) interface{}, 2)
 	dayFunctions[8][1] = day08.Part1
 	dayFunctions[8][2] = day08.Part2
+	dayFunctions[9] = make(map[int]func(puzzle aoclib.Puzzle) interface{}, 2)
+	dayFunctions[9][1] = day09.Part1
+	dayFunctions[9][2] = day09.Part2
 }
 
 func execute(thisDay int) {