2024-day12

Author: liamgallear

2024/day12/.bench

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+{"Lines":[{"Name":"Part 1","N":196,"NsPerOp":6034676,"AllocedBytesPerOp":0,"AllocsPerOp":0,"MBPerS":0,"Measured":1,"Ord":0},{"Name":"Part 2","N":132,"NsPerOp":9227806,"AllocedBytesPerOp":0,"AllocsPerOp":0,"MBPerS":0,"Measured":1,"Ord":0}],"Measured":1}

2024/day12/README.md

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+<!-- You can add some comments here if you want to :D -->

2024/day12/main.go

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+package main
+
+import (
+	_ "embed"
+	"os"
+)
+
+//go:embed input.txt
+var input string
+
+//go:embed input_test.txt
+var inputTest string
+
+func main() {
+	// Check argv if we use test input or not
+	if len(os.Args) > 1 && os.Args[1] == "test" {
+		input = inputTest
+	}
+
+	answer := doPartOne(input)
+	println(answer)
+
+	answer = doPartTwo(input)
+	println(answer)
+}

2024/day12/main_test.go

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+package main
+
+import "testing"
+
+func BenchmarkPartOne(b *testing.B) {
+	for n := 0; n < b.N; n++ {
+		doPartOne(input)
+	}
+}
+
+func BenchmarkPartTwo(b *testing.B) {
+	for n := 0; n < b.N; n++ {
+		doPartTwo(input)
+	}
+}

2024/day12/part1.go

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+package main
+
+import (
+	"aocli/utils/maps"
+	"aocli/utils/reader"
+	"image"
+)
+
+func doPartOne(input string) int {
+	mapper := maps.MakeImagePointMap(reader.FileLineByLine(input))
+	seen := make(map[image.Point]bool)
+	var delta = []image.Point{{0, 1}, {1, 0}, {0, -1}, {-1, 0}}
+	var res int
+	for i, r := range mapper {
+		if seen[i] {
+			continue
+		}
+		NP := []image.Point{i}
+		var area, perim int
+		for len(NP) > 0 {
+			P := NP[0]
+			NP = NP[1:]
+			if seen[P] {
+				continue
+			}
+			area++
+
+			seen[P] = true
+			for _, d := range delta {
+				np := P.Add(d)
+				if _, ok := mapper[np]; mapper[np] == r && ok {
+					NP = append(NP, np)
+					continue
+				}
+				perim++
+			}
+		}
+		res += area * perim
+	}
+	return res
+}

2024/day12/part2.go

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+package main
+
+import (
+	"aocli/utils/maps"
+	"aocli/utils/reader"
+	"image"
+	"slices"
+)
+
+func doPartTwo(input string) int {
+	mapper := maps.MakeImagePointMap(reader.FileLineByLine(input))
+	seen := make(map[image.Point]bool)
+	var delta = []image.Point{{0, 1}, {1, 0}, {0, -1}, {-1, 0}}
+	var res int
+	for i, r := range mapper {
+		if seen[i] {
+			continue
+		}
+		NP := []image.Point{i}
+		sides := make(map[image.Point][]image.Point)
+		var area int
+		for len(NP) > 0 {
+			P := NP[0]
+			NP = NP[1:]
+			if seen[P] {
+				continue
+			}
+			area++
+
+			seen[P] = true
+			for _, d := range delta {
+				np := P.Add(d)
+				if _, ok := mapper[np]; mapper[np] == r && ok {
+					NP = append(NP, np)
+					continue
+				}
+				if _, ok := sides[d]; !ok {
+					sides[d] = []image.Point{}
+				}
+				sides[d] = append(sides[d], P)
+			}
+		}
+		var S int
+		for _, s := range sides {
+			sideseen := make(map[image.Point]bool)
+			for _, i := range s {
+				if _, ok := sideseen[i]; ok {
+					continue
+				}
+				S++
+				NP := []image.Point{i}
+				for len(NP) > 0 {
+					P := NP[0]
+					NP = NP[1:]
+					if sideseen[P] {
+						continue
+					}
+					sideseen[P] = true
+					for _, dd := range delta {
+						np := P.Add(dd)
+						if slices.Contains(s, np) {
+							NP = append(NP, np)
+						}
+					}
+				}
+			}
+		}
+		res += area * S
+	}
+	return res
+}