Added POTD solution of 10th october

[horrible-hacker]

🚀 What does this PR do?

• Adds solution for LeetCode Daily Challenge on 10 October in C++.
• To solve this problem I have used monotonic stack, i have taken all the elements from the left in a stack such that they follow this pattern i.e. nums[j]<stack.top() and after making this stack, i have started from right to start poping elements from the stack if they follow this condition i.e nums[j]>=stack.top(), if they do follow these condition then i pop that element from stack and also calculate j-i for that instance.

📝 Issue Reference:

Fixes issue: # 10

🔍 Checklist:

Please ensure the following before submitting your PR:

• I have placed my solution in the correct folder (solutions/dayXX/).
• [T] My code follows clean coding practices and is efficient.
• I have added comments in my code to explain the approach.
• I have updated the README.md for the specific day with a brief explanation of my solution.
• [T] I have tested the solution on LeetCode and it works correctly.

🔧 Solution Details:

• Language Used: C++
• Time Complexity: O(N)
• Space Complexity: O(N)

🌟 Additional Notes (if any):

Screenshot of above Solution

[horrible-hacker]

I have also moved solution.cpp file from day10 folder to day09 folder.