From f83219ecdf2e7f8bb3fdaae8d460b1ee4ef1350b Mon Sep 17 00:00:00 2001
From: dimitrijjedich <dimitrij@startup-werk.de>
Date: Mon, 25 Nov 2024 05:10:48 +0100
Subject: [PATCH 1/3] initial commit

---
 algorithms/isertion.go | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 algorithms/isertion.go

diff --git a/algorithms/isertion.go b/algorithms/isertion.go
new file mode 100644
index 0000000..2ac9a99
--- /dev/null
+++ b/algorithms/isertion.go
@@ -0,0 +1,5 @@
+package algorithms
+
+func InsertionSort(arr []int) []int {
+	return arr
+}

From 76cc43ac06106caf17bf8f4af2b64a87def6429f Mon Sep 17 00:00:00 2001
From: dimitrijjedich <dimitrij@startup-werk.de>
Date: Mon, 25 Nov 2024 07:37:37 +0100
Subject: [PATCH 2/3] add initial implementation

---
 algorithms/isertion.go | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/algorithms/isertion.go b/algorithms/isertion.go
index 2ac9a99..4cd9a2a 100644
--- a/algorithms/isertion.go
+++ b/algorithms/isertion.go
@@ -1,5 +1,19 @@
 package algorithms
 
 func InsertionSort(arr []int) []int {
-	return arr
+	n := len(arr)
+	result := make([]int, n)
+	copy(result, arr)
+
+	for i := 0; i < n; i++ {
+		for j, element := i-1, result[i]; j >= 0; j-- {
+			if element < result[j] {
+				result[j], result[j+1] = result[j+1], result[j]
+			} else {
+				result[j+1] = element
+				break
+			}
+		}
+	}
+	return result
 }

From ecc5aa955e787301d577ad83128c05de5698cf5b Mon Sep 17 00:00:00 2001
From: dimitrijjedich <dimitrij@startup-werk.de>
Date: Mon, 25 Nov 2024 07:37:54 +0100
Subject: [PATCH 3/3] add tests for insertion sort algorithm

---
 algorithms_test/insertion_test.go | 33 +++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 algorithms_test/insertion_test.go

diff --git a/algorithms_test/insertion_test.go b/algorithms_test/insertion_test.go
new file mode 100644
index 0000000..0c9761c
--- /dev/null
+++ b/algorithms_test/insertion_test.go
@@ -0,0 +1,33 @@
+package algorithms_test
+
+import (
+	"github.com/dimitrijjedich/go-algorithms/algorithms"
+	"reflect"
+	"testing"
+)
+
+func TestInsertionSort(t *testing.T) {
+	testCases := []struct {
+		name     string
+		input    []int
+		expected []int
+	}{
+		{"already sorted", []int{1, 2, 3, 4, 5}, []int{1, 2, 3, 4, 5}},
+		{"reverse sorted", []int{5, 4, 3, 2, 1}, []int{1, 2, 3, 4, 5}},
+		{"unsorted array", []int{5, 3, 8, 6, 2}, []int{2, 3, 5, 6, 8}},
+		{"non consecutive array", []int{9, 3, 5, 1, 7}, []int{1, 3, 5, 7, 9}},
+		{"empty array", []int{}, []int{}},
+		{"single element", []int{42}, []int{42}},
+		{"duplicates", []int{3, 1, 2, 3, 1}, []int{1, 1, 2, 3, 3}},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.name, func(t *testing.T) {
+			result := algorithms.InsertionSort(testCase.input)
+
+			if !reflect.DeepEqual(result, testCase.expected) {
+				t.Errorf("Failed %s: expected %v, got %v", testCase.name, testCase.expected, result)
+			}
+		})
+	}
+}