day02

2025/go/day02/day02.go

@@ -0,0 +1,59 @@
+package day02
+
+import (
+	"adventofcode2025/utils"
+	"fmt"
+	"strings"
+)
+
+func Part1(input string) int {
+	ranges := strings.Split(input, ",")
+	count := 0
+	for _, r := range ranges {
+		min_s, max_s := strings.Split(r, "-")[0], strings.Split(r, "-")[1]
+		min := utils.MustAtoi(min_s)
+		max := utils.MustAtoi(max_s)
+		for i := min; i <= max; i++ {
+			s := fmt.Sprintf("%d", i)
+			if len(s)%2 != 0 {
+				continue
+			}
+			if s[:len(s)/2] != s[len(s)/2:] {
+				continue
+			}
+			count += utils.MustAtoi(s)
+		}
+	}
+	return count
+}
+
+func Part2(input string) int {
+	ranges := strings.Split(input, ",")
+	count := 0
+	for _, r := range ranges {
+		min_s, max_s := strings.Split(r, "-")[0], strings.Split(r, "-")[1]
+		min := utils.MustAtoi(min_s)
+		max := utils.MustAtoi(max_s)
+		for i := min; i <= max; i++ {
+			s := fmt.Sprintf("%d", i)
+			for numDigits := 1; numDigits <= len(s)/2; numDigits++ {
+				if len(s)%numDigits != 0 {
+					continue
+				}
+				found := true
+				for j := 1; j < len(s)/numDigits; j++ {
+					if s[0:numDigits] != s[j*numDigits:(j+1)*numDigits] {
+						found = false
+						break
+					}
+
+				}
+				if found {
+					count += utils.MustAtoi(s)
+					break
+				}
+			}
+		}
+	}
+	return count
+}