Added leetcode solutions

[diva-21]

• File(s) Modified: _0041 - First Missing Positive, 0290 - Word Pattern,1930 - Unique Length 3 Palindromic Subsequences
• Language(s) Used: cpp
• Submission URL: _ https://leetcode.com/problems/word-pattern/submissions/868580925/ , https://leetcode.com/problems/unique-length-3-palindromic-subsequences/submissions/868581664/ , https://leetcode.com/problems/first-missing-positive/submissions/868581995/

[tahsintunan]

Please rename the files as per the instructions given here

[diva-21]

Please rename the files as per the instructions given here

I have made the changes as per instructed @tahsintunan

[tahsintunan]

Please rename the files as per the instructions given here

I have made the changes as per instructed @tahsintunan

Make sure the problem-number is formatted as four digits adding leading zeroes if necessary (e.g. 0041 instead of 41, 0290 instead of 290)

[diva-21]

Please rename the files as per the instructions given here

I have made the changes as per instructed @tahsintunan

Make sure the problem-number is formatted as four digits adding leading zeroes if necessary (e.g. 0041 instead of 41, 0290 instead of 290)

changes did,sorry for silly mistakes @tahsintunan

[tahsintunan]

Thank you.