From ab208bdb80a4a600d808ef041ac79151692942f6 Mon Sep 17 00:00:00 2001
From: Simon <hello@gamersi.at>
Date: Sun, 22 Dec 2024 11:09:35 +0100
Subject: [PATCH] day22p1

---
 day22p1/solution.go      | 40 ++++++++++++++++++++++++++++++++++++++++
 day22p1/solution_test.go | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 76 insertions(+)
 create mode 100644 day22p1/solution.go
 create mode 100644 day22p1/solution_test.go

diff --git a/day22p1/solution.go b/day22p1/solution.go
new file mode 100644
index 0000000..c347dc9
--- /dev/null
+++ b/day22p1/solution.go
@@ -0,0 +1,40 @@
+package day22p1
+
+import (
+	"io"
+	"strconv"
+
+	"aoc/utils"
+)
+
+func Solve(r io.Reader) any {
+	lines := utils.ReadLines(r)
+
+	sum := 0
+	for _, line := range lines {
+		initialSecretNum, _ := strconv.Atoi(line)
+		newSecretNum := initialSecretNum
+		for i := 0; i < 2000; i++ {
+			newSecretNum = evolveSecretNum(newSecretNum)
+		}
+		sum += newSecretNum
+	}
+
+	return sum
+}
+
+func evolveSecretNum(initialSecretNum int) int {
+	secretNum := initialSecretNum
+	secretNum = prune(mix(secretNum, secretNum*64))
+	secretNum = prune(mix(secretNum, secretNum/32))
+	secretNum = prune(mix(secretNum, secretNum*2048))
+	return secretNum
+}
+
+func mix(a, b int) int {
+	return a ^ b
+}
+
+func prune(a int) int { // modulo 16777216 (2^24)
+	return a & 0xFFFFFF
+}
diff --git a/day22p1/solution_test.go b/day22p1/solution_test.go
new file mode 100644
index 0000000..d236c4b
--- /dev/null
+++ b/day22p1/solution_test.go
@@ -0,0 +1,36 @@
+package day22p1
+
+import (
+	"strings"
+	"testing"
+
+	"aoc/utils"
+)
+
+var testInput = `1
+10
+100
+2024`
+
+func TestSolve(t *testing.T) {
+	tests := []struct {
+		input  string
+		answer int
+	}{
+		{testInput, 37327623},
+	}
+
+	if testing.Verbose() {
+		utils.Verbose = true
+	}
+
+	for _, test := range tests {
+		r := strings.NewReader(test.input)
+
+		result := Solve(r).(int)
+
+		if result != test.answer {
+			t.Errorf("Expected %d, got %d", test.answer, result)
+		}
+	}
+}