2025 day12

Author: liamgallear

2025/day12/.bench

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+{"Lines":[{"Name":"Part 1","N":3043,"NsPerOp":373346,"AllocedBytesPerOp":0,"AllocsPerOp":0,"MBPerS":0,"Measured":1,"Ord":0}],"Measured":1}

2025/day12/README.md

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

2025/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)
+}

2025/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)
+	}
+}

2025/day12/part1.go

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+package main
+
+import (
+	"aocli/utils"
+	"fmt"
+	"strings"
+)
+
+func doPartOne(input string) int {
+	parts := strings.Split(strings.TrimSpace(input), "\n\n")
+
+	// Precompute present counts (count '#' symbols in each present pattern)
+	numPresents := len(parts) - 1
+	presents := make([]int, numPresents)
+	for i := 0; i < numPresents; i++ {
+		presents[i] = strings.Count(parts[i], "#")
+	}
+
+	ans := 0
+	lines := strings.Split(parts[numPresents], "\n")
+
+	for _, line := range lines {
+		// Parse dimensions and gift counts
+		colonIdx := strings.Index(line, ": ")
+		if colonIdx == -1 {
+			continue
+		}
+
+		var x, y int
+		fmt.Sscanf(line[:colonIdx], "%dx%d", &x, &y)
+		area := x * y
+
+		// Calculate total present area
+		totalpresentarea := 0
+		giftStart := colonIdx + 2
+		for i := 0; giftStart < len(line); i++ {
+			// Parse next number
+			spaceIdx := strings.IndexByte(line[giftStart:], ' ')
+			var numStr string
+			if spaceIdx == -1 {
+				numStr = line[giftStart:]
+				giftStart = len(line)
+			} else {
+				numStr = line[giftStart : giftStart+spaceIdx]
+				giftStart += spaceIdx + 1
+			}
+			totalpresentarea += utils.Atoi(numStr) * presents[i]
+		}
+
+		// Check if sleigh has enough space
+		if totalpresentarea <= area && area > totalpresentarea+(totalpresentarea/5) {
+			ans++
+		}
+	}
+
+	return ans
+}