Analyze the time and space complexity of your solution. Compare your solution to others and identify areas for improvement.

Users will be able to choose a name made up of letters, numbers, dots, and underscores. Usernames won't be able to start with "www." or end in something like ".com." This is specifically to ...

Reports have revealed that WhatsApp is testing a ‘personal handles’ feature that will eradicate the need for cell numbers on the app. WhatsApp on phone with blurred background / iStock ...