============This is a Contribution list for Hactoberfest PRs========

1.Zeeshan
    Contribution=Updated Hello.cpp and Added a feature to greet the user as per his/her name
    
    
2.Ojaswi Pande
    Contribution=Add Trees and Linked List which is helpful for beginners.
    
    
3.Saikiran
    Contribution=Added a additional model XGbooster in titanic_machine_learning_from_disaster and trained it like a new feature without disturbing the existing code.
