day02 solution

2018/day02/part1/main.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"adventofcode/util"
+	"fmt"
+	"strings"
+)
+
+func main() {
+	input := util.ReadFile("../input.txt")
+	lines := strings.Split(input, "\n")
+
+	var twos, threes int
+	for _, boxID := range lines {
+		if hasTwo(boxID) {
+			twos++
+		}
+		if hasThree(boxID) {
+			threes++
+		}
+	}
+
+	fmt.Println("checksum", twos*threes)
+}
+
+func hasTwo(box string) bool {
+	chars := make(map[rune]int)
+	for _, c := range box {
+		chars[c]++
+	}
+	for _, v := range chars {
+		if v == 2 {
+			return true
+		}
+	}
+	return false
+}
+
+func hasThree(box string) bool {
+	chars := make(map[rune]int)
+	for _, c := range box {
+		chars[c]++
+	}
+	for _, v := range chars {
+		if v == 3 {
+			return true
+		}
+	}
+	return false
+}