1 files changed, 64 insertions, 0 deletions
diff --git a/day25/main.go b/day25/main.go
new file mode 100644
index 0000000..907c397
--- /dev/null
+++ b/day25/main.go
@@ -0,0 +1,64 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+)
+
+func main() {
+	fmt.Println(part1(readData("example.txt")), 3)
+	fmt.Println(part1(readData("data.txt")), 3)
+}
+
+type Data struct {
+	keys  [][5]int
+	locks [][5]int
+}
+
+func fits(k, l [5]int) bool {
+	for i := range k {
+		if k[i]+l[i] > 5 {
+			return false
+		}
+	}
+	return true
+}
+
+func part1(data Data) (count int) {
+	for _, k := range data.keys {
+		for _, l := range data.locks {
+			if fits(k, l) {
+				count++
+			}
+		}
+	}
+	return
+}
+
+func readData(fileName string) (data Data) {
+	data = Data{}
+	fp, _ := os.Open(fileName)
+	scanner := bufio.NewScanner(fp)
+
+	for scanner.Scan() {
+		isKey := scanner.Text()[0] == '.'
+		code := [5]int{0, 0, 0, 0, 0}
+		for i := 0; scanner.Scan() && i < 5; i++ {
+			line := scanner.Text()
+			for j := range 5 {
+				if line[j] == '#' {
+					code[j]++
+				}
+			}
+		}
+		scanner.Scan()
+		if isKey {
+			data.keys = append(data.keys, code)
+		} else {
+			data.locks = append(data.locks, code)
+		}
+	}
+
+	return
+}