From 7ccb2ea522dbaf7bf58e321230b2a5fb2e7664f1 Mon Sep 17 00:00:00 2001
From: xkm <xkm@xkm.be>
Date: Mon, 11 May 2026 19:07:09 +0800
Subject: [PATCH] 1-B-1

---
 .gitignore         |  2 ++
 1-B-1/go.mod       |  3 +++
 1-B-1/main.go      | 11 +++++++++++
 1-B-1/main_test.go | 41 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 57 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 1-B-1/go.mod
 create mode 100644 1-B-1/main.go
 create mode 100644 1-B-1/main_test.go

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..090a1f0
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+.idea
+.DS_Store
diff --git a/1-B-1/go.mod b/1-B-1/go.mod
new file mode 100644
index 0000000..55596da
--- /dev/null
+++ b/1-B-1/go.mod
@@ -0,0 +1,3 @@
+module algo
+
+go 1.26.2
diff --git a/1-B-1/main.go b/1-B-1/main.go
new file mode 100644
index 0000000..6ab85b8
--- /dev/null
+++ b/1-B-1/main.go
@@ -0,0 +1,11 @@
+package algo
+
+import "cmp"
+
+func FindMax[T cmp.Ordered](arr []T) T {
+	if len(arr) == 1 {
+		return arr[0]
+	}
+	mid := len(arr) / 2
+	return max(FindMax[T](arr[:mid]), FindMax[T](arr[mid:]))
+}
diff --git a/1-B-1/main_test.go b/1-B-1/main_test.go
new file mode 100644
index 0000000..76a282f
--- /dev/null
+++ b/1-B-1/main_test.go
@@ -0,0 +1,41 @@
+package algo
+
+import (
+	"fmt"
+	"math/rand/v2"
+	"testing"
+)
+
+func TestFindMax(t *testing.T) {
+	for range 114 {
+		arr := make([]int64, 114)
+		for idx := range arr {
+			arr[idx] = rand.Int64()
+		}
+		expectedResult := arr[0]
+		for _, val := range arr {
+			expectedResult = max(expectedResult, val)
+		}
+		if expectedResult != FindMax(arr) {
+			t.Failed()
+		}
+	}
+}
+
+func BenchmarkFindMax(b *testing.B) {
+	sizes := []int{10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000}
+
+	for _, n := range sizes {
+		b.Run(fmt.Sprintf("N=%d", n), func(b *testing.B) {
+			arr := make([]int64, n)
+			for idx := range arr {
+				arr[idx] = rand.Int64()
+			}
+
+			b.ResetTimer()
+			for b.Loop() {
+				FindMax(arr)
+			}
+		})
+	}
+}