2025 day 3

2025/Day-03/day03.go

@@ -0,0 +1,83 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func partOne() int {
+	file, err := os.Open("input.txt")
+	if err != nil {
+		log.Fatalf("failed to open file: %s", err)
+	}
+	defer file.Close()
+	scanner := bufio.NewScanner(file)
+	tot := 0
+	for scanner.Scan() {
+		line := scanner.Text()
+		splitLine := strings.Split(line, "")
+		biggest := -1
+		for i, n := range splitLine {
+			for _, x := range splitLine[(i + 1):] {
+				num, _ := strconv.Atoi((n + x))
+				if num > biggest {
+					biggest = num
+				}
+			}
+		}
+		tot += biggest
+	}
+	return tot
+}
+
+func findBiggest(nums []int, minLen int, start int) int {
+	nums = nums[start:]
+	max := 0
+	for i, n := range nums {
+		if len(nums)-(i+1) < minLen {
+			break
+		}
+		if n > nums[max] {
+			max = i
+		}
+	}
+	return max + start
+}
+
+func partTwo() int {
+	file, err := os.Open("input.txt")
+	if err != nil {
+		log.Fatalf("failed to open file: %s", err)
+	}
+	defer file.Close()
+	scanner := bufio.NewScanner(file)
+	tot := 0
+	for scanner.Scan() {
+		line := scanner.Text()
+		splitLine := strings.Split(line, "")
+		nums := []int{}
+		for _, s := range splitLine {
+			i, _ := strconv.Atoi(s)
+			nums = append(nums, i)
+		}
+		joltage := ""
+		min := 0
+		for i := 11; i >= 0; i-- {
+			newBiggest := findBiggest(nums, i, min)
+			joltage += strconv.Itoa(nums[newBiggest])
+			min = newBiggest + 1
+		}
+		joltageInt, _ := strconv.Atoi(joltage)
+		tot += joltageInt
+	}
+	return tot
+}
+
+func main() {
+	fmt.Println(partOne())
+	fmt.Println(partTwo())
+}