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Created August 24, 2018 11:52
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Copy of Nanda Javarma's Work
def binary_search(the_array, item, start, end):
if start == end:
if the_array[start] > item:
return start
return start + 1
if start > end:
return start
mid = round((start + end)/ 2)
if the_array[mid] < item:
return binary_search(the_array, item, mid + 1, end)
elif the_array[mid] > item:
return binary_search(the_array, item, start, mid - 1)
return mid
Insertion sort that timsort uses if the array size is small or if
the size of the "run" is small
def insertion_sort(the_array):
l = len(the_array)
for index in range(1, l):
value = the_array[index]
pos = binary_search(the_array, value, 0, index - 1)
the_array = the_array[:pos] + [value] + the_array[pos:index] + the_array[index+1:]
return the_array
def merge(left, right):
"""Takes two sorted lists and returns a single sorted list by comparing the
elements one at a time.
[1, 2, 3, 4, 5, 6]
if not left:
return right
if not right:
return left
if left[0] < right[0]:
return [left[0]] + merge(left[1:], right)
return [right[0]] + merge(left, right[1:])
def timsort(the_array):
runs, sorted_runs = [], []
length = len(the_array)
new_run = [the_array[0]]
# for every i in the range of 1 to length of array
for i in range(1, length):
# if i is at the end of the list
if i == length - 1:
# if the i'th element of the array is less than the one before it
if the_array[i] < the_array[i-1]:
# if new_run is set to None (NULL)
if not new_run:
new_run = []
# else if its equal to or more than
# for every item in runs, append it using insertion sort
for item in runs:
# for every run in sorted_runs, merge them
sorted_array = []
for run in sorted_runs:
sorted_array = merge(sorted_array, run)
timsort([2, 3, 1, 5, 6, 7])
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