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Doctest and typing for longest_increasing_subsequence.py (#1526)

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* Update longest_increasing_subsequence.py

* Update longest_increasing_subsequence.py

* Format longest_increasing_subsequence.py to PEP8

* Update longest_increasing_subsequence.py
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John Law 2019-11-05 02:06:16 +08:00 committed by GitHub
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dynamic_programming/longest_increasing_subsequence.py
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@ -4,42 +4,52 @@ Author : Mehdi ALAOUI
This is a pure Python implementation of Dynamic Programming solution to the longest increasing subsequence of a given sequence.
The problem is :
Given an ARRAY, to find the longest and increasing sub ARRAY in that given ARRAY and return it.
Given an array, to find the longest and increasing sub-array in that given array and return it.
Example: [10, 22, 9, 33, 21, 50, 41, 60, 80] as input will return [10, 22, 33, 41, 60, 80] as output
"""
from typing import List
def longestSub(ARRAY): # This function is recursive
ARRAY_LENGTH = len(ARRAY)
def longest_subsequence(array: List[int]) -> List[int]: # This function is recursive
"""
Some examples
>>> longest_subsequence([10, 22, 9, 33, 21, 50, 41, 60, 80])
[10, 22, 33, 41, 60, 80]
>>> longest_subsequence([4, 8, 7, 5, 1, 12, 2, 3, 9])
[1, 2, 3, 9]
>>> longest_subsequence([9, 8, 7, 6, 5, 7])
[8]
>>> longest_subsequence([1, 1, 1])
[1, 1, 1]
"""
array_length = len(array)
if (
ARRAY_LENGTH <= 1
array_length <= 1
): # If the array contains only one element, we return it (it's the stop condition of recursion)
return ARRAY
return array
# Else
PIVOT = ARRAY[0]
pivot = array[0]
isFound = False
i = 1
LONGEST_SUB = []
while not isFound and i < ARRAY_LENGTH:
if ARRAY[i] < PIVOT:
longest_subseq = []
while not isFound and i < array_length:
if array[i] < pivot:
isFound = True
TEMPORARY_ARRAY = [element for element in ARRAY[i:] if element >= ARRAY[i]]
TEMPORARY_ARRAY = longestSub(TEMPORARY_ARRAY)
if len(TEMPORARY_ARRAY) > len(LONGEST_SUB):
LONGEST_SUB = TEMPORARY_ARRAY
temp_array = [element for element in array[i:] if element >= array[i]]
temp_array = longest_subsequence(temp_array)
if len(temp_array) > len(longest_subseq):
longest_subseq = temp_array
else:
i += 1
TEMPORARY_ARRAY = [element for element in ARRAY[1:] if element >= PIVOT]
TEMPORARY_ARRAY = [PIVOT] + longestSub(TEMPORARY_ARRAY)
if len(TEMPORARY_ARRAY) > len(LONGEST_SUB):
return TEMPORARY_ARRAY
temp_array = [element for element in array[1:] if element >= pivot]
temp_array = [pivot] + longest_subsequence(temp_array)
if len(temp_array) > len(longest_subseq):
return temp_array
else:
return LONGEST_SUB
return longest_subseq
# Some examples
print(longestSub([4, 8, 7, 5, 1, 12, 2, 3, 9]))
print(longestSub([9, 8, 7, 6, 5, 7]))
if __name__ == "__main__":
import doctest
doctest.testmod()