feat: added LeetCode problem 1,2

[nageshnnazare]

Created new directory for leetcode solutions, updated DIRECTORY.md and README.md

Description of Change

Checklist

• [x] Added description of change
• [x] Added file name matches File name guidelines
• [x] Added tests and example, test must pass
• [x] Added documentation so that the program is self-explanatory and educational - Doxygen guidelines
• [x] Relevant documentation/comments is changed or added
• [x] PR title follows semantic commit guidelines
• [x] Search previous suggestions before making a new one, as yours may be a duplicate.
• [x] I acknowledge that all my contributions will be made under the project's license.

Notes:

[nageshnnazare]

Hi @Panquesito7, @tjgurwara99 For problem 2, the CI is failing with the following warnings:

/home/runner/work/C-Plus-Plus/C-Plus-Plus/leetcode/src/2.cpp:29:9: warning: assigning newly created 'gsl::owner<>' to non-owner 'ListNode *' [cppcoreguidelines-owning-memory] sum->next = new ListNode(val%10); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /home/runner/work/C-Plus-Plus/C-Plus-Plus/leetcode/src/2.cpp:35:9: warning: assigning newly created 'gsl::owner<>' to non-owner 'ListNode *' [cppcoreguidelines-owning-memory] sum->next = new ListNode(carry); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I guess it is because of the use of raw pointers instead of smart pointers. Is there a way to suppress this?

(This may require changing the definition of the ListNode struct, which is already defined by the platform)

struct ListNode { int val; std::unique_ptr<ListNode> next; // Use unique_ptr here ... };

[realstealthninja]

Does this directory also fall under doxygen style guidelines?

[Panquesito7]

Does this directory also fall under doxygen style guidelines?

I believe so. Not required, but if added, it's better, IMO.

[Panquesito7]

Is there a way to suppress this?

It'd be better to use smart pointers, though. I found this to convert raw to a smart pointer, it may help: https://www.sololearn.com/Discuss/1958592/how-can-i-replace-raw-pointers-with-smart-pointers

[realstealthninja]

Does this directory also fall under doxygen style guidelines?

I believe so. Not required, but if added, it's better, IMO.

Ah alright!

[github-actions[bot]]

This pull request has been automatically marked as abandoned because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[github-actions[bot]]

This pull request has been automatically marked as abandoned because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[github-actions[bot]]

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