Day 4 part 1

main.go

@@ -15,6 +15,9 @@ func main() {
 
 	runAndBenchmark("03", "1", false, solutions.Day03Part01)
 	runAndBenchmark("03", "2", false, solutions.Day03Part02)
+
+	runAndBenchmark("04", "1", false, solutions.Day04Part01)
+	runAndBenchmark("04", "2", false, solutions.Day04Part02)
 }
 
 type execute func(bool) int

solutions/day04.go

@@ -0,0 +1,41 @@
+package solutions
+
+import (
+	"regexp"
+	"strings"
+)
+
+func Day04Part01(isTest bool) int {
+	input := ReadInput("04", isTest)
+	passports := strings.Split(input, "\n\n")
+
+	regex, _ := regexp.Compile("(\\w+:[\\w#]+)")
+
+	correctAmount := 0
+
+	for _, passport := range passports {
+		matches := regex.FindAllString(passport, -1)
+
+		values := make(map[string]string)
+
+		for _, match := range matches {
+			colonPosition := strings.Index(match, ":")
+			key := match[:colonPosition]
+			value := match[colonPosition+1:]
+			values[key] = value
+		}
+
+		_, cidMissing := values["cid"]
+		keysAmount := len(values)
+
+		if keysAmount == 8 || (keysAmount == 7 && !cidMissing) {
+			correctAmount += 1
+		}
+	}
+
+	return correctAmount
+}
+
+func Day04Part02(isTest bool) int {
+	return -1
+}