Insertion Sort

def insertion_sort(arr):
    # save array's length
    N = len(arr)

    for i in range(1, N):
        # assign a pointer to the start of the loop
        j = i

        # loop while the pointer is > 0 and the previous item is greater than it
        while j > 0 and arr[j] < arr[j - 1]:
            # swap the pointer item with it's left item
            arr[j], arr[j-1] = arr[j-1], arr[j]
            # decrease the pointer
            j -= 1

insertionSort(array of numbers)
  for i = 1 to i = length(array) - 1
    j = i

    while j > 0 and array[j] < array[j - 1]
        swap array[j] and array[j-1]
        j = j - 1