From 35f9f4540c075a2663b8f628fd4f14cc8d579a46 Mon Sep 17 00:00:00 2001
From: Hugo Venega <hugo.venega.00>
Date: Thu, 18 Nov 2021 10:44:40 -0300
Subject: [PATCH 1/3] Create shellSort function

---
 src/sort/shell/shellSort.spec.ts |  9 +++++++++
 src/sort/shell/shellSort.ts      | 19 +++++++++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 src/sort/shell/shellSort.spec.ts
 create mode 100644 src/sort/shell/shellSort.ts

diff --git a/src/sort/shell/shellSort.spec.ts b/src/sort/shell/shellSort.spec.ts
new file mode 100644
index 0000000..ddd94b1
--- /dev/null
+++ b/src/sort/shell/shellSort.spec.ts
@@ -0,0 +1,9 @@
+import shellSort from './shellSort';
+
+describe('shell sort', () => {
+  it('It should return an array sorted from lowest to highest', () => {
+    const arrayToSort = [43, 65, 44, 12, 67, 1, 9, 33, 21];
+    const expectedArray = [1, 9, 12, 21, 33, 43, 44, 65, 67];
+    expect(shellSort(arrayToSort)).toEqual(expectedArray);
+  });
+});
diff --git a/src/sort/shell/shellSort.ts b/src/sort/shell/shellSort.ts
new file mode 100644
index 0000000..05483f3
--- /dev/null
+++ b/src/sort/shell/shellSort.ts
@@ -0,0 +1,19 @@
+export default function shellSort(array: number[]): number[] {
+  const introducedArray = array;
+  const n = introducedArray.length;
+
+  for (let gap = Math.floor(n / 2); gap > 0; gap = Math.floor(gap / 2)) {
+    for (let i = gap; i < n; i += 1) {
+      const temp = introducedArray[i];
+
+      let j;
+      for (j = i; j >= gap && introducedArray[j - gap] > temp; j -= gap) {
+        introducedArray[j] = introducedArray[j - gap];
+      }
+
+      introducedArray[j] = temp;
+    }
+  }
+
+  return introducedArray;
+}

From e0ba5b333f3bd81c77e581c57fdf6c7c8ec7d195 Mon Sep 17 00:00:00 2001
From: Hugo Venega <hugo.venega.00>
Date: Thu, 18 Nov 2021 15:13:39 -0300
Subject: [PATCH 2/3] Improve tests of shellSort function

---
 src/sort/shell/shellSort.spec.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/sort/shell/shellSort.spec.ts b/src/sort/shell/shellSort.spec.ts
index ddd94b1..6ba2187 100644
--- a/src/sort/shell/shellSort.spec.ts
+++ b/src/sort/shell/shellSort.spec.ts
@@ -1,7 +1,7 @@
 import shellSort from './shellSort';
 
 describe('shell sort', () => {
-  it('It should return an array sorted from lowest to highest', () => {
+  it('should return an array sorted from lowest to highest', () => {
     const arrayToSort = [43, 65, 44, 12, 67, 1, 9, 33, 21];
     const expectedArray = [1, 9, 12, 21, 33, 43, 44, 65, 67];
     expect(shellSort(arrayToSort)).toEqual(expectedArray);

From 5439c1d70a5c41a1aedf0e46df4fc3d03f538df9 Mon Sep 17 00:00:00 2001
From: Hugo Venega <hugo.venega.00>
Date: Thu, 18 Nov 2021 16:12:51 -0300
Subject: [PATCH 3/3] Add tests for shellsort function

---
 src/sort/shell/shellSort.spec.ts | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/src/sort/shell/shellSort.spec.ts b/src/sort/shell/shellSort.spec.ts
index 6ba2187..d192374 100644
--- a/src/sort/shell/shellSort.spec.ts
+++ b/src/sort/shell/shellSort.spec.ts
@@ -1,6 +1,27 @@
 import shellSort from './shellSort';
 
 describe('shell sort', () => {
+  it('should return an empty array when the array for sorting is empty', () => {
+    const arrayToSort: number[] = [];
+    const expectedArray: number[] = [];
+    expect(shellSort(arrayToSort))
+      .toEqual(expectedArray);
+  });
+
+  it('should return an array with the element', () => {
+    const arrayToSort: number[] = [14];
+    const expectedArray: number[] = [14];
+    expect(shellSort(arrayToSort))
+      .toEqual(expectedArray);
+  });
+
+  it('should return an array with two elements sorted from lowest to highest', () => {
+    const arrayToSort = [65, 43];
+    const expectedArray = [43, 65];
+    expect(shellSort(arrayToSort))
+      .toEqual(expectedArray);
+  });
+
   it('should return an array sorted from lowest to highest', () => {
     const arrayToSort = [43, 65, 44, 12, 67, 1, 9, 33, 21];
     const expectedArray = [1, 9, 12, 21, 33, 43, 44, 65, 67];