Insertion sort works as follows.

• The array of values to be sorted is divided into two partitions: the partition of sorted values and that of unsorted values.
• In each step of insertion sorting, the first element in the unsorted partition is picked up and is inserted into an appropriate position in the sorted partition.
• The sorting proceeds until the elements in the unsorted partition are exhausted.
• We use floorIdx to designate the last element in the sorted partition.
• The array elements with indexes 0 through floorIdx are in the partition of sorted values, and the rest in the patition of unsorted values.
• The first element of the unsorted partition has array index floorIdx + 1.
• Initially, only the first element in the array belongs to the sorted partition, and hence floorIdx = 0.
• While the slot where the insertion should occur is searched for, sorted values greater than the value to be inserted are pushed down within the sorted partition.
• Sorted values are shown in blue, and unsorted values in green.