Insertion Sort: Introduction• Algorithm for sorting elements in array• Algorithm sorts the numbers in place• Do not have to allocate additional storage• Simply rearranges the numbers in the array

• “Left” side is always sorted• Will see in demonstration

• Java implementation will use ArrayLists and Generics • Anything that implements Java’s compareTo can be used

Insertion Sort: The Algorithm• Select the element to be compared• Start at the second element (index: 1) and continue to the last

element (index: array to be sorted length – 1)• Compare this element to elements preceding it • Exchange with preceding elements until the element to be

compared is greater than a preceding element or the start of the array is reached

• Repeat

Insertion Sort: Analysis• Efficient algorithm for sorting a small number of

elements• Best Case (Already Sorted)• O(n)• Don’t have to go through the ”while” loop

• Average-Case and Worst Case• O(n2)