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Update tim_sort.py (TheAlgorithms#972)
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* Update tim_sort.py


Update tim_sort.py

The previous algorithm was skipping numbers, according to issue TheAlgorithms#959, and my own tests.
The version I am applying uses a while loop, which works correctly and is easier to compute, as there is no break statement.

* Update tim_sort.py
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FrogBattle authored and cclauss committed Jul 30, 2019
1 parent 861a8c3 commit e58a5e6
Showing 1 changed file with 24 additions and 23 deletions.
47 changes: 24 additions & 23 deletions sorts/tim_sort.py
Original file line number Diff line number Diff line change
@@ -1,10 +1,6 @@
from __future__ import print_function
def binary_search(lst, item, start, end):
if start == end:
if lst[start] > item:
return start
else:
return start + 1
return start if lst[start] > item else start + 1
if start > end:
return start

Expand All @@ -23,7 +19,7 @@ def insertion_sort(lst):
for index in range(1, length):
value = lst[index]
pos = binary_search(lst, value, 0, index - 1)
lst = lst[:pos] + [value] + lst[pos:index] + lst[index+1:]
lst = lst[:pos] + [value] + lst[pos:index] + lst[index + 1 :]

return lst

Expand All @@ -42,30 +38,34 @@ def merge(left, right):


def tim_sort(lst):
runs, sorted_runs = [], []
"""
>>> tim_sort("Python")
['P', 'h', 'n', 'o', 't', 'y']
>>> tim_sort((1.1, 1, 0, -1, -1.1))
[-1.1, -1, 0, 1, 1.1]
>>> tim_sort(list(reversed(list(range(7)))))
[0, 1, 2, 3, 4, 5, 6]
>>> tim_sort([3, 2, 1]) == insertion_sort([3, 2, 1])
True
>>> tim_sort([3, 2, 1]) == sorted([3, 2, 1])
True
"""
length = len(lst)
runs, sorted_runs = [], []
new_run = [lst[0]]
sorted_array = []

for i in range(1, length):
if i == length - 1:
new_run.append(lst[i])
runs.append(new_run)
break

i = 1
while i < length:
if lst[i] < lst[i - 1]:
if not new_run:
runs.append([lst[i - 1]])
new_run.append(lst[i])
else:
runs.append(new_run)
new_run = []
runs.append(new_run)
new_run = [lst[i]]
else:
new_run.append(lst[i])
i += 1
runs.append(new_run)

for run in runs:
sorted_runs.append(insertion_sort(run))

for run in sorted_runs:
sorted_array = merge(sorted_array, run)

Expand All @@ -74,9 +74,10 @@ def tim_sort(lst):

def main():

lst = [5,9,10,3,-4,5,178,92,46,-18,0,7]
lst = [5, 9, 10, 3, -4, 5, 178, 92, 46, -18, 0, 7]
sorted_lst = tim_sort(lst)
print(sorted_lst)

if __name__ == '__main__':

if __name__ == "__main__":
main()

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