From 0e9ea6f679b33467bd292333d1430498604e70ee Mon Sep 17 00:00:00 2001
From: Alexander Rundberg <alex@gwai.se>
Date: Wed, 25 Dec 2024 19:14:16 +0100
Subject: [PATCH] Add solution day 25 part 1

---
 README.md                |  2 +-
 solutions/day25/main.go  | 27 ++++++++++++++-
 solutions/day25/parse.go | 72 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 99 insertions(+), 2 deletions(-)
 create mode 100644 solutions/day25/parse.go

diff --git a/README.md b/README.md
index f61cfd8..f64a955 100644
--- a/README.md
+++ b/README.md
@@ -57,5 +57,5 @@ automatically rebuilt and redeployed every time the `common` module or their own
 | 09  | ⭐ ⭐      | 22  | ⭐ ⭐      |
 | 10  | ⭐ ⭐      | 23  | ⭐ ⭐      |
 | 11  | ⭐ ⭐      | 24  | ⭐ ⭐      |
-| 12  | ⭐ ⭐      | 25  |          |
+| 12  | ⭐ ⭐      | 25  | ⭐        |
 | 13  | ⭐ ⭐      |     |          |
diff --git a/solutions/day25/main.go b/solutions/day25/main.go
index 0f0bade..e0f38f9 100644
--- a/solutions/day25/main.go
+++ b/solutions/day25/main.go
@@ -1,9 +1,34 @@
 package main
 
 import (
+	"fmt"
 	"github.com/terminalnode/adventofcode2024/common"
 )
 
 func main() {
-	common.Setup(25, nil, nil)
+	common.Setup(25, part1, nil)
+}
+
+func part1(
+	input string,
+) string {
+	keys, locks := parse(input)
+	count := 0
+	for _, key := range keys {
+		for _, lock := range locks {
+			allOk := true
+			for i, keyN := range key.a {
+				lockN := lock.a[i]
+				if keyN+lockN > 7 {
+					allOk = false
+					break
+				}
+			}
+			if allOk {
+				count++
+			}
+		}
+	}
+
+	return fmt.Sprintf("Number of ok key-lock combos: %d", count)
 }
diff --git a/solutions/day25/parse.go b/solutions/day25/parse.go
new file mode 100644
index 0000000..b598ab3
--- /dev/null
+++ b/solutions/day25/parse.go
@@ -0,0 +1,72 @@
+package main
+
+import (
+	"strconv"
+	"strings"
+)
+
+type entryType int
+type keyArray []entry
+type lockArray []entry
+
+const (
+	KEY = entryType(iota)
+	LOCK
+)
+
+type entry struct {
+	t    entryType
+	a    []int
+	aInv []int
+	s    string
+	sInv string
+}
+
+func parse(
+	input string,
+) (keyArray, lockArray) {
+	split := strings.Split(input, "\n\n")
+	keys := make(keyArray, 0, len(split))
+	locks := make(lockArray, 0, len(split))
+
+	for _, rawEntry := range split {
+		lines := strings.Split(rawEntry, "\n")
+
+		a := []int{0, 0, 0, 0, 0}
+		aInv := []int{7, 7, 7, 7, 7}
+		for _, line := range lines {
+			for x, ch := range line {
+				if ch == '#' {
+					a[x] += 1
+					aInv[x] -= 1
+				}
+			}
+		}
+		s := arrToString(a)
+		sInv := arrToString(aInv)
+
+		if lines[0] == "#####" {
+			locks = append(locks, entry{
+				t: LOCK,
+				a: a, aInv: aInv,
+				s: s, sInv: sInv})
+		} else {
+			keys = append(keys, entry{
+				t: KEY,
+				a: a, aInv: aInv,
+				s: s, sInv: sInv})
+		}
+	}
+
+	return keys, locks
+}
+
+func arrToString(
+	arr []int,
+) string {
+	sArr := make([]string, len(arr))
+	for i, n := range arr {
+		sArr[i] = strconv.Itoa(n)
+	}
+	return strings.Join(sArr, ",")
+}