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Added Median of Medians Algorithm #9864

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Merged
merged 5 commits into from
Oct 8, 2023

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coderbeta1
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Describe your change:

Added an Algorithm: Added Median of medians algorithm to find element at rank k in time complexity O(n)

  • Add an algorithm?
  • Fix a bug or typo in an existing algorithm?
  • Documentation change?

Checklist:

  • I have read CONTRIBUTING.md.
  • This pull request is all my own work -- I have not plagiarized.
  • I know that pull requests will not be merged if they fail the automated tests.
  • This PR only changes one algorithm file. To ease review, please open separate PRs for separate algorithms.
  • All new Python files are placed inside an existing directory.
  • All filenames are in all lowercase characters with no spaces or dashes.
  • All functions and variable names follow Python naming conventions.
  • All function parameters and return values are annotated with Python type hints.
  • All functions have doctests that pass the automated testing.
  • All new algorithms include at least one URL that points to Wikipedia or another similar explanation.
  • If this pull request resolves one or more open issues then the description above includes the issue number(s) with a closing keyword: "Fixes #ISSUE-NUMBER".

@algorithms-keeper algorithms-keeper bot added the awaiting reviews This PR is ready to be reviewed label Oct 5, 2023
@algorithms-keeper algorithms-keeper bot added the tests are failing Do not merge until tests pass label Oct 5, 2023
Comment on lines 10 to 20

"""
>>> quick_select([2, 4, 5, 7, 899, 54, 32], 5)
32
>>> quick_select([2, 4, 5, 7, 899, 54, 32], 1)
2
>>> quick_select([5, 4, 3, 2], 2)
3
>>> quick_select([3, 5, 7, 10, 2, 12], 3)
5
"""
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Suggested change
"""
>>> quick_select([2, 4, 5, 7, 899, 54, 32], 5)
32
>>> quick_select([2, 4, 5, 7, 899, 54, 32], 1)
2
>>> quick_select([5, 4, 3, 2], 2)
3
>>> quick_select([3, 5, 7, 10, 2, 12], 3)
5
"""

There is no point in repeating the same tests here.

Comment on lines 24 to 38
"""
>>> median_of_five([2, 4, 5, 7, 899])
5
>>> median_of_five([5, 7, 899, 54, 32])
32
>>> median_of_five([5, 4, 3, 2])
3
>>> median_of_five([3, 5, 7, 10, 2])
5
"""
"""
Return the median of the input list
:param arr: Array to find median of
:return: median of arr
"""
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Can you swap the order of the tests and explanation, and condense into a single docstring

Comment on lines 44 to 59
"""
>>> median_of_medians([2, 4, 5, 7, 899, 54, 32])
54
>>> median_of_medians([5, 7, 899, 54, 32])
32
>>> median_of_medians([5, 4, 3, 2])
4
>>> median_of_medians([3, 5, 7, 10, 2, 12])
12
"""
"""
Return a pivot to partition data on by calculating
Median of medians of input data
:param arr: The data to be checked (a list)
:return: median of medians of input array
"""
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Can you swap the order of the tests and explanation, and condense into a single docstring

Comment on lines 74 to 91
"""
>>> quick_select([2, 4, 5, 7, 899, 54, 32], 5)
32
>>> quick_select([2, 4, 5, 7, 899, 54, 32], 1)
2
>>> quick_select([5, 4, 3, 2], 2)
3
>>> quick_select([3, 5, 7, 10, 2, 12], 3)
5
"""

"""
Two way partition the data into smaller and greater lists,
in relationship to the pivot
:param arr: The data to be searched (a list)
:param target: The rank to be searched
:return: element at rank target
"""
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Can you swap the order of the tests and explanation, and condense into a single docstring

Comment on lines 29 to 30
>>> median_of_five([5, 4, 3, 2])
3
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This test is failing:

>>> median_of_five([5, 4, 3, 2])
Expected:
    3
Got:
    4

@algorithms-keeper algorithms-keeper bot removed the tests are failing Do not merge until tests pass label Oct 6, 2023
@coderbeta1 coderbeta1 requested a review from ChrisO345 October 6, 2023 12:34
@ChrisO345 ChrisO345 merged commit 17de908 into TheAlgorithms:master Oct 8, 2023
@algorithms-keeper algorithms-keeper bot removed the awaiting reviews This PR is ready to be reviewed label Oct 8, 2023
sedatguzelsemme pushed a commit to sedatguzelsemme/Python that referenced this pull request Sep 15, 2024
* Added Median of Medians Algorithm

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update median_of_medians.py as per requested changes

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
@isidroas isidroas mentioned this pull request Jan 25, 2025
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2 participants