add aoc 2025 day 3 solution

2025/3/main.go

@@ -0,0 +1,65 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+)
+
+func main() {
+	// iterate over all IDs
+	joltages := Decode("input.txt")
+
+	var joltagessum int = 0
+
+	for _, i := range joltages {
+		var tensColumn int = 0
+		var onesColumn int = 0
+
+		for iteration, x := range i {
+			num, err := strconv.Atoi(string(x))
+			if err != nil {
+				panic(err)
+			}
+
+			if tensColumn == 0 {
+				tensColumn = num
+			} else if num > tensColumn && iteration != len(i)-1 {
+				tensColumn = num
+				onesColumn = 0
+			} else if num > onesColumn && onesColumn >= tensColumn {
+				tensColumn = onesColumn
+				onesColumn = num
+			} else if num > onesColumn {
+				onesColumn = num
+			}
+		}
+
+		sum := tensColumn*10 + onesColumn
+		fmt.Printf("joltage found for %s, %d%d %d\n", i, tensColumn, onesColumn, sum)
+		joltagessum = joltagessum + sum
+	}
+
+	fmt.Println("total joltage sum", joltagessum)
+}
+
+func Decode(filename string) []string {
+	f, err := os.Open(filename)
+
+	if err != nil {
+		panic(err)
+	}
+
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	var joltages []string
+
+	for scanner.Scan() {
+		// extract joltage numbers into struct to go over
+		joltages = append(joltages, scanner.Text())
+	}
+
+	return joltages
+}