2025 Day05

Author: liamgallear

2025/day05/.bench

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+{"Lines":[{"Name":"Part 1","N":13522,"NsPerOp":85678,"AllocedBytesPerOp":0,"AllocsPerOp":0,"MBPerS":0,"Measured":1,"Ord":0},{"Name":"Part 2","N":455313,"NsPerOp":2629,"AllocedBytesPerOp":0,"AllocsPerOp":0,"MBPerS":0,"Measured":1,"Ord":0}],"Measured":1}

2025/day05/README.md

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

2025/day05/main.go

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+package main
+
+import (
+	"aocli/utils"
+	_ "embed"
+	"fmt"
+	"os"
+	"slices"
+	"strings"
+)
+
+//go:embed input.txt
+var input string
+
+//go:embed input_test.txt
+var inputTest string
+
+type fresh struct {
+	start, end int
+}
+
+var ranges []fresh
+var sections []string
+
+func main() {
+	// Check argv if we use test input or not
+	if len(os.Args) > 1 && os.Args[1] == "test" {
+		input = inputTest
+	}
+
+	// Parse input once
+	sections = strings.Split(strings.TrimSpace(input), "\n\n")
+	parseRanges()
+
+	answer := doPartOne()
+	println(answer)
+
+	answer = doPartTwo()
+	println(answer)
+}
+
+func parseRanges() {
+	rangeLines := strings.Split(sections[0], "\n")
+	ranges = make([]fresh, len(rangeLines))
+	for i, v := range rangeLines {
+		fmt.Sscanf(v, "%d-%d", &ranges[i].start, &ranges[i].end)
+	}
+}
+
+func mergeRanges() []fresh {
+	// Sort and merge overlapping ranges
+	sorted := make([]fresh, len(ranges))
+	copy(sorted, ranges)
+
+	slices.SortFunc(sorted, func(a, b fresh) int {
+		return a.start - b.start
+	})
+
+	merged := make([]fresh, 0, len(sorted))
+	current := sorted[0]
+
+	for i := 1; i < len(sorted); i++ {
+		if sorted[i].start <= current.end+1 {
+			// Overlapping or adjacent, merge them
+			current.end = utils.Biggest(current.end, sorted[i].end)
+		} else {
+			// No overlap, save current and start new
+			merged = append(merged, current)
+			current = sorted[i]
+		}
+	}
+	merged = append(merged, current)
+
+	return merged
+}

2025/day05/main_test.go

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+package main
+
+import (
+	"strings"
+	"testing"
+)
+
+func BenchmarkPartOne(b *testing.B) {
+	// Parse input once before benchmark
+	sections = strings.Split(strings.TrimSpace(input), "\n\n")
+	parseRanges()
+
+	b.ResetTimer()
+	for n := 0; n < b.N; n++ {
+		doPartOne()
+	}
+}
+
+func BenchmarkPartTwo(b *testing.B) {
+	// Parse input once before benchmark
+	sections = strings.Split(strings.TrimSpace(input), "\n\n")
+	parseRanges()
+
+	b.ResetTimer()
+	for n := 0; n < b.N; n++ {
+		doPartTwo()
+	}
+}

2025/day05/part1.go

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+package main
+
+import (
+	"aocli/utils"
+	"strings"
+)
+
+func doPartOne() int {
+	ans := 0
+	for _, v := range strings.Split(sections[1], "\n") {
+		ingr := utils.Atoi(v)
+		for _, r := range ranges {
+			if ingr >= r.start && ingr <= r.end {
+				ans++
+				break
+			}
+		}
+	}
+	return ans
+}

2025/day05/part2.go

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+package main
+
+func doPartTwo() int {
+	merged := mergeRanges()
+
+	ans := 0
+	for _, r := range merged {
+		ans += r.end - r.start + 1
+	}
+
+	return ans
+}