feat(2025): add day3

2025/day3/day3.go

@@ -0,0 +1,88 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+)
+
+func runeToInt(r rune) int {
+	return int(r - '0')
+}
+
+func getLargestJoltage(raw string) int {
+	runes := []rune(raw)
+	i1 := 0
+	n1 := runes[i1]
+	for i := i1; i < len(runes)-1; i++ {
+		if runes[i] > n1 {
+			i1 = i
+			n1 = runes[i1]
+			// fmt.Printf("i: %v, n1: %v\n", i, n1)
+		}
+	}
+	i2 := i1 + 1
+	n2 := runes[i2]
+	for j := i2 + 1; j < len(runes); j++ {
+		if runes[j] > n2 {
+			i2 = j
+			n2 = runes[i2]
+			// fmt.Printf("j: %v, n2: %v\n", j, n2)
+		}
+	}
+	return runeToInt(n1)*10 + runeToInt(n2)
+}
+
+func part1() {
+	data, _ := os.ReadFile("input.txt")
+	content := strings.TrimSpace(string(data))
+	lines := strings.Split(content, "\n")
+	sum := 0
+	for _, line := range lines {
+		maxJoltage := getLargestJoltage(line)
+		// fmt.Println(maxJoltage)
+		sum += maxJoltage
+	}
+	fmt.Printf("%d\n", sum)
+}
+
+func getLargestJoltage2(raw string) int {
+	runes := []rune(raw)
+	num := 12
+	r := [12]rune{}
+	i := -1
+	for idx := range num {
+		i++
+		r[idx] = runes[i]
+		for j := i + 1; j < len(runes)-(num-idx-1); j++ {
+			if runes[j] > r[idx] {
+				i = j
+				r[idx] = runes[i]
+			}
+		}
+	}
+	result := 0
+	for i := range num {
+		result *= 10
+		result += runeToInt(r[i])
+	}
+	return result
+}
+
+func part2() {
+	data, _ := os.ReadFile("input.txt")
+	content := strings.TrimSpace(string(data))
+	lines := strings.Split(content, "\n")
+	sum := 0
+	for _, line := range lines {
+		maxJoltage := getLargestJoltage2(line)
+		// fmt.Println(maxJoltage)
+		sum += maxJoltage
+	}
+	fmt.Printf("%d\n", sum)
+}
+
+func main() {
+	part1()
+	part2()
+}

2025/day3/go.mod

@@ -0,0 +1,3 @@
+module day3
+
+go 1.23.4