# Examples Used in Class

• ### 11/11/2020 Sorting Algorithm ComparisonsSorting Algorithms with cards (YouTube) (quicksort)Quicksort is not stableMore Sorting Algorithms with cards (YouTube)Sorting Algorithms Illustrated in dance (yep) (YouTube)Yet More Sorting Algorithms Illustrated (YouTube)

• 11/11/2020
selection sort
```Selection sort is not stable

let's sort these array elements:

10  8  8'  2  5  element
-- -- --  -- --
0  1  2   3  4  index

Note that 8 comes before the 8' ... so if selection sort is stable,
when the array is sorted, 8 will still be before 8'

Steps:

1) find smallest item in array to go into index 0 ... this is 2 at index 3
swap [0] and [3], leaves this array

2  8  8' 10  5  element
-- -- --  -- --
0  1  2   3  4  index

2) find smallest item in array from index 1 up... this is 5 at index 4
swap [1] and [4], leaves this array

2  5  8' 10  8  element
-- -- --  -- --
0  1  2   3  4  index

3) find smallest item in array from index 2 up... find that 8' is smallest
meaning nothing remaining is larger
so no swap, leaves this unchanged array

2  5  8' 10  8  element
-- -- --  -- --
0  1  2   3  4  index

4) find smallest item in array from index 3 up... this is 8 at index 4
swap [3] and [4], leaves this array

2  5  8'  8 10  element
-- -- --  -- --
0  1  2   3  4  index

And finally note that now 8' is first and 8 is second,
so selection sort is unstable.
```