Selection sort exercise

algorithms/7_SelectionSort/selection_sort.py

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+
+def selection_sort(elements):
+    for x in range(len(elements)):
+        #Set smallest index unsorted
+        minIndex=x
+        for y in range(x,len(elements)):
+            if elements[y]<elements[minIndex]:##Check if the element at y index is smaller than current minimum
+                minIndex=y##Set new Minimum Index
+        ##Swap the minimum number with first unsorted number
+        if x!=minIndex:
+            elements[x],elements[minIndex]=elements[minIndex],elements[x]
+
+if __name__ == '__main__':
+    #
+    tests = [
+        [11,9,29,7,2,15,28],
+        [3, 7, 9, 11],
+        [25, 22, 21, 10],
+        [29, 15, 28],
+        [],
+        [6]
+    ]
+
+    for elements in tests:
+        print(f'Given unsorted array: {elements}')
+        selection_sort(elements)
+        print(f'Array after Sorting : {elements}')
+        print()

algorithms/7_SelectionSort/selection_sort_exercise.md

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+# Exercise: Selection Sort
+
+Implement a Milti-Level Sort of a given list of dictionaries. A single dictionary entry contains two keys 'First Name' and 'Last Name'. the list should be sorted first based on 'First Name', then based on 'Last Name', w.r.t. common/same 'First Name' entries.
+
+
+
+For example, given the sequence List:
+
+```
+[
+    {'First Name': 'Raj', 'Last Name': 'Nayyar'},
+    {'First Name': 'Suraj', 'Last Name': 'Sharma'},
+    {'First Name': 'Karan', 'Last Name': 'Kumar'},
+    {'First Name': 'Jade', 'Last Name': 'Canary'},
+    {'First Name': 'Raj', 'Last Name': 'Thakur'},
+    {'First Name': 'Raj', 'Last Name': 'Sharma'},
+    {'First Name': 'Kiran', 'Last Name': 'Kamla'},
+    {'First Name': 'Armaan', 'Last Name': 'Kumar'},
+    {'First Name': 'Jaya', 'Last Name': 'Sharma'},
+    {'First Name': 'Ingrid', 'Last Name': 'Galore'},
+    {'First Name': 'Jaya', 'Last Name': 'Seth'},
+    {'First Name': 'Armaan', 'Last Name': 'Dadra'},
+    {'First Name': 'Ingrid', 'Last Name': 'Maverick'},
+    {'First Name': 'Aahana', 'Last Name': 'Arora'}
+]
+```
+
+
+Your algorithm should generate sorted list:
+
+```
+[
+    {'First Name': 'Aahana', 'Last Name': 'Arora'}
+    {'First Name': 'Armaan', 'Last Name': 'Dadra'}
+    {'First Name': 'Armaan', 'Last Name': 'Kumar'}
+    {'First Name': 'Ingrid', 'Last Name': 'Galore'}
+    {'First Name': 'Ingrid', 'Last Name': 'Maverick'}
+    {'First Name': 'Jade', 'Last Name': 'Canary'}
+    {'First Name': 'Jaya', 'Last Name': 'Seth'}
+    {'First Name': 'Jaya', 'Last Name': 'Sharma'}
+    {'First Name': 'Karan', 'Last Name': 'Kumar'}
+    {'First Name': 'Kiran', 'Last Name': 'Kamla'}
+    {'First Name': 'Raj', 'Last Name': 'Nayyar'}
+    {'First Name': 'Raj', 'Last Name': 'Sharma'}
+    {'First Name': 'Raj', 'Last Name': 'Thakur'}
+    {'First Name': 'Suraj', 'Last Name': 'Sharma'}
+]
+```
+
+
+
+
+
+ [Solution](https://github.com/codebasics/data-structures-algorithms-python/blob/master/algorithms/7_SelectionSort/selection_sort_exercise_solution.py)

algorithms/7_SelectionSort/selection_sort_exercise_solution.py

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+def multilevel_selection_sort(elements, sort_by_list):
+    for sort_by in sort_by_list[-1::-1]:
+        for x in range(len(elements)):
+            min_index = x
+            for y in range(x, len(elements)):
+                if elements[y][sort_by] < elements[min_index][sort_by]:
+                    min_index = y
+            if x != min_index:
+                elements[x], elements[min_index] = elements[min_index], elements[x]
+
+
+if __name__ == '__main__':
+    elements = [
+        {'First Name': 'Raj', 'Last Name': 'Nayyar'},
+        {'First Name': 'Suraj', 'Last Name': 'Sharma'},
+        {'First Name': 'Karan', 'Last Name': 'Kumar'},
+        {'First Name': 'Jade', 'Last Name': 'Canary'},
+        {'First Name': 'Raj', 'Last Name': 'Thakur'},
+        {'First Name': 'Raj', 'Last Name': 'Sharma'},
+        {'First Name': 'Kiran', 'Last Name': 'Kamla'},
+        {'First Name': 'Armaan', 'Last Name': 'Kumar'},
+        {'First Name': 'Jaya', 'Last Name': 'Sharma'},
+        {'First Name': 'Ingrid', 'Last Name': 'Galore'},
+        {'First Name': 'Jaya', 'Last Name': 'Seth'},
+        {'First Name': 'Armaan', 'Last Name': 'Dadra'},
+        {'First Name': 'Ingrid', 'Last Name': 'Maverick'},
+        {'First Name': 'Aahana', 'Last Name': 'Arora'}
+    ]
+
+    print(f'Given unsorted array:', *elements, sep='\n')
+    multilevel_selection_sort(
+        elements, ['First Name', 'Last Name'])
+    print(f'Array after Multi-Level Sorting:', *elements, sep='\n')