I currently have to use a separate timer to check how long I am working on a problem. To make life easy and similar to how the contests work, here's the proposal for this feature:

• Have an option for the user to set a configurable timer for a question.
• Calculate the time taken by the user to solve the question and use it as an attribute for the question. Similar to Easy/Medium/Hard, something like <30min/30-60min/>60min avg time taken.
• Present stats of the time taken to solve question similar to memory and run time after the completion.