Add skip list

[zhangzhuang15]

Pull Request Template

Description

Add skip list.

Type of change

Please delete options that are not relevant.

• New feature (non-breaking change which adds functionality)

Checklist:

• I ran bellow commands using the latest version of rust nightly.
• I ran cargo clippy --all -- -D warnings just before my last commit and fixed any issue that was found.
• I ran cargo fmt just before my last commit.
• I ran cargo test just before my last commit and all tests passed.
• I added my algorithm to the corresponding mod.rs file within its own folder, and in any parent folder(s).
• I added my algorithm to DIRECTORY.md with the correct link.
• I checked COUNTRIBUTING.md and my code follows its guidelines.

Please make sure that if there is a test that takes too long to run ( > 300ms), you #[ignore] that or
try to optimize your code or make the test easier to run. We have this rule because we have hundreds of
tests to run; If each one of them took 300ms, we would have to wait for a long time.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 98.64253% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 95.43%. Comparing base (21f5615) to head (c310c08).
⚠️ Report is 3 commits behind head on master.

Files with missing lines	Patch %	Lines
src/data_structures/skip_list.rs	98.64%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #954      +/-   ##
==========================================
+ Coverage   95.39%   95.43%   +0.04%     
==========================================
  Files         332      335       +3     
  Lines       21496    21797     +301     
==========================================
+ Hits        20506    20803     +297     
- Misses        990      994       +4     

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[zhangzhuang15]

@imp2002 Hey, could you give me some feedback ? This is my first time to join open source project.

[zhangzhuang15]

@siriak Could you take your spare time to give me some feedback ? I don't know what happened and what this project status is, imp2002 is not active for reviewing code.

[Copilot]

Pull request overview

This PR adds a skip list data structure implementation to the algorithms repository. A skip list is a probabilistic data structure that provides O(log n) average time complexity for search, insertion, and deletion operations through multiple levels of linked lists with random balancing.

Key Changes

• Implements a generic SkipList<K, V> data structure with insert, search, delete operations
• Includes an iterator implementation for traversing the skip list in sorted order
• Adds comprehensive test coverage for core operations

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 9 comments.

File	Description
src/data_structures/skip_list.rs	New skip list implementation with unsafe pointer-based node management and probabilistic level generation
src/data_structures/mod.rs	Exports the new SkipList struct to make it publicly available

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[siriak]

Please address the comments where relevant and then I can merge the PR

[zhangzhuang15]

Please address the comments where relevant and then I can merge the PR

Thanks for your feedback, I'll do it later.

[zhangzhuang15]

@siriak Comments are resolved. It's really a nice experience for me to give PR for this project. By the way, I also have another PR #952, which fixes a bug in rb_tree.rs file, would you mind taking a look at it ? Thank you.

[siriak]

Looks good, thanks!