GH-149: add Python Sorting (#150)

Author: quang-ph

README.md

@@ -100,6 +100,7 @@ A data structure is a data organization, management, and storage format that is
 <td>Sorting</td>
 <td>
 <a href="/concepts/cpp/sorting.md"><code>cpp🐀</code></a>
+<a href="/concepts/python/sorting.md"><code>py🐍</code></a>
 </td>
 </tr>
 <tr>

concepts/python/sorting.md

@@ -0,0 +1,110 @@
+# Sorting
+
+From wikipedia
+
+> Sorting refers to ordering data in an increasing or decreasing manner according to some linear relationship among the
+> data items. Ordering: arranging items in a sequence ordered by some criterion. Categorizing: grouping items with
+> similar properties.
+
+## 🎨 Design
+
+**Sorting Techniques**
+
+|                | Definition                                                                                                                                                           |
+|----------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| Bubble Sort    | Repeatedly compares two adjacent elements and swaps them if they are in the wrong order                                                                              |
+| Selection Sort | Repeatedly finds the minimum element and sort it in order                                                                                                            |
+| Insertion Sort | This sorting algorithm maintains a sub-array that is always sorted. Values from the unsorted part of the array are placed at the correct position in the sorted part |
+
+## 📈 Complexity Analysis
+
+| Sort type      | Complexity |
+|----------------|------------|
+| Bubble Sort    | $O(n^2)$   |
+| Selection Sort | $O(n^2)$   |
+| Insertion Sort | $O(n^2)$   |
+
+## 💻 Implementation in Python
+
+Python has built-in function `sorted`.
+
+```python
+array = [8, 5, 9, 2, 1]  # [8, 5, 9, 2, 1]
+sorted(array)  # [1, 2, 5, 8, 9]
+
+words = ['banana', 'pie', 'Washington', 'book']  # ['banana', 'pie', 'Washington', 'book']
+sorted(words, key=len)  # ['pie', 'book', 'banana', 'Washington']
+```
+
+Implement Bubble Sort in Python
+
+```python
+def bubble_sort(array):
+    n = len(array)
+    for i in range(n):
+        already_sorted = True
+
+        for j in range(n - i - 1):
+            if array[j] > array[j + 1]:
+                array[j], array[j + 1] = array[j + 1], array[j]
+                already_sorted = False
+
+        if already_sorted:
+            break
+    return array
+
+
+array = [8, 5, 9, 2, 1]  # [8, 5, 9, 2, 1]
+bubble_sort(array)  # [1, 2, 5, 8, 9]
+```
+
+Implement Selection Sort in Python
+
+```python
+def selection_sort(array):
+    n = len(array)
+    for i in range(n):
+        min_idx = i
+
+        for j in range(i + 1, n):
+            if array[j] < array[min_idx]:
+                min_idx = j
+
+        array[i], array[min_idx] = array[min_idx], array[i]
+    return array
+
+
+array = [8, 5, 9, 2, 1]  # [8, 5, 9, 2, 1]
+selection_sort(array)  # [1, 2, 5, 8, 9]
+```
+
+Implement Insertion Sort in Python
+
+```python
+def insertion_sort(array):
+    for i in range(1, len(array)):
+        key_item = array[i]
+        j = i - 1
+
+        while j >= 0 and array[j] > key_item:
+            # Shift the value one position to the left
+            # and reposition j to point to the next element
+            # (from right to left)
+            array[j + 1] = array[j]
+            j -= 1
+
+        array[j + 1] = key_item
+    return array
+
+
+array = [8, 5, 9, 2, 1]  # [8, 5, 9, 2, 1]
+insertion_sort(array)  # [1, 2, 5, 8, 9]
+```
+
+## 🔗 Further Reading
+
+* [Sorting](https://en.wikipedia.org/wiki/Sorting), wikipedia
+* [Sorting Algorithms in Python](https://realpython.com/sorting-algorithms-python/), realpython
+* [How to Use sorted() and sort() in Python](https://realpython.com/python-sort/), realpython
+* [Sorting Algorithms in Python](https://www.geeksforgeeks.org/sorting-algorithms-in-python/), geeksforgeeks 2022
+* ▶️ [Python Sorting Algorithms](https://www.youtube.com/playlist?list=PLj8W7XIvO93rJHSYzkk7CgfiLQRUEC2Sq), Joe James, 2015