2023-05

2023/05/01.go

@@ -0,0 +1,92 @@
+package main
+
+import (
+	"embed"
+	"fmt"
+	"strings"
+
+	"github.com/dbut2/advent-of-code/pkg/sti"
+	"github.com/dbut2/advent-of-code/pkg/test"
+	"github.com/dbut2/advent-of-code/pkg/utils"
+)
+
+//go:embed input.txt
+var input string
+
+//go:embed test*.txt
+var tests embed.FS
+
+func main() {
+	t := test.Register(tests, solve)
+	t.Expect(1, 35)
+	fmt.Println(solve(input))
+}
+
+func solve(input string) int {
+	s := utils.ParseInput(input)
+
+	var seeds []int
+	var mappings []mapping
+
+	currentMapping := mapping{}
+	for _, line := range s {
+		if line == "" {
+			continue
+		}
+
+		if strings.Contains(line, "seeds: ") {
+			seedsString := strings.Split(line, "seeds: ")
+			seedList := strings.Split(seedsString[1], " ")
+			for _, seedItem := range seedList {
+				seeds = append(seeds, sti.Sti(seedItem))
+			}
+			continue
+		}
+
+		if strings.Contains(line, "-") {
+			if len(currentMapping) > 0 {
+				mappings = append(mappings, currentMapping)
+			}
+			currentMapping = mapping{}
+			continue
+		}
+
+		values := strings.Split(line, " ")
+
+		currentMapping = append(currentMapping, submapping{
+			source: sti.Sti(values[1]),
+			size:   sti.Sti(values[2]),
+			offset: sti.Sti(values[0]) - sti.Sti(values[1]),
+		})
+	}
+	if len(currentMapping) > 0 {
+		mappings = append(mappings, currentMapping)
+	}
+
+	lowest := -1
+	for _, seed := range seeds {
+		val := seed
+
+		for _, mapping := range mappings {
+			for _, submapping := range mapping {
+				if val >= submapping.source && val <= submapping.source+submapping.size {
+					val += submapping.offset
+					break
+				}
+			}
+		}
+
+		if lowest == -1 {
+			lowest = val
+		}
+		lowest = min(lowest, val)
+	}
+
+	return lowest
+}
+
+type mapping []submapping
+
+type submapping struct {
+	source, size, offset int
+}

2023/05/02.go

@@ -0,0 +1,119 @@
+package main
+
+import (
+	"embed"
+	"fmt"
+	"strings"
+
+	"github.com/dbut2/advent-of-code/pkg/sti"
+	"github.com/dbut2/advent-of-code/pkg/test"
+	"github.com/dbut2/advent-of-code/pkg/utils"
+)
+
+//go:embed input.txt
+var input string
+
+//go:embed test*.txt
+var tests embed.FS
+
+func main() {
+	t := test.Register(tests, solve)
+	t.Expect(2, 46)
+	fmt.Println(solve(input))
+}
+
+func solve(input string) int {
+	s := utils.ParseInput(input)
+
+	var seedPairs [][2]int
+	var mappings []mapping
+
+	currentMapping := mapping{}
+	for _, line := range s {
+		if line == "" {
+			continue
+		}
+
+		if strings.Contains(line, "seeds: ") {
+			seedsString := strings.Split(line, "seeds: ")
+			seedList := strings.Split(seedsString[1], " ")
+
+			for i := 0; i < len(seedList); i += 2 {
+				seedPairs = append(seedPairs, [2]int{sti.Sti(seedList[i]), sti.Sti(seedList[i]) + sti.Sti(seedList[i+1])})
+			}
+			continue
+		}
+
+		if strings.Contains(line, "-") {
+			if len(currentMapping) > 0 {
+				mappings = append(mappings, currentMapping)
+			}
+			currentMapping = mapping{}
+			continue
+		}
+
+		values := strings.Split(line, " ")
+
+		currentMapping = append(currentMapping, submapping{
+			source: sti.Sti(values[1]),
+			size:   sti.Sti(values[2]),
+			offset: sti.Sti(values[0]) - sti.Sti(values[1]),
+		})
+	}
+	if len(currentMapping) > 0 {
+		mappings = append(mappings, currentMapping)
+	}
+
+	lowest := -1
+
+	for _, pair := range seedPairs {
+		ranges := [][2]int{pair}
+
+		for _, mapping := range mappings {
+			for _, submapping := range mapping {
+				ranges = splitRangesAt(ranges, submapping.source)
+			}
+
+			for i := range ranges {
+				ranges[i][0] = mapping.convert(ranges[i][0])
+				ranges[i][1] = mapping.convert(ranges[i][1])
+			}
+		}
+
+		for i := range ranges {
+			if lowest == -1 {
+				lowest = ranges[i][0]
+			}
+
+			lowest = min(lowest, ranges[i][0])
+		}
+	}
+
+	return lowest
+}
+
+type mapping []submapping
+
+type submapping struct {
+	source, size, offset int
+}
+
+func (m mapping) convert(in int) int {
+	for _, c := range m {
+		if in >= c.source && in <= c.source+c.size {
+			return in + c.offset
+		}
+	}
+	return in
+}
+
+func splitRangesAt(s [][2]int, n int) [][2]int {
+	for i, ss := range s {
+		if n > ss[0] && n <= ss[1] {
+			s[i][1] = n - 1
+			s = append(s, [2]int{n, ss[1]})
+			return s
+		}
+	}
+	return s
+}