add cpp solution to lc problem no:68

[Dhoni77]

0068.Text Justification

[YangFong]

I found that I could not select that line, I wanted to say Markdown code block, need to add cpp

[Dhoni77]

I found that I could not select that line, I wanted to say Markdown code block, need to add cpp

ok done!

[yanglbme]

Please create a Solution.cpp file and add the solution to it. And I'll close #740 @Dhoni77

[Dhoni77]

Please create a Solution.cpp file and add the solution to it. And I'll close #740 @Dhoni77

Ok doing it now

[yanglbme]

Thanks for contributing! I'll format your code before merging into main branch. @Dhoni77

[Dhoni77]

Thank you @yanglbme and @YangFong.
This is my first contribution and I'll try to contribute more😍