Solving Coding Problems

For coding problems, when you write a program on the problem screen and submit it, it is automatically graded.

Screen Layout

The problem screen is divided into the following three areas from left to right. The button at the top right of each area lets you collapse or restore that area.

Area	Content
Problem statement	Problem text, input and output format, execution time and memory limits
Editor	Prepare your code in the Editor, Template, and Upload tabs
Submit / Review	Submit, Debug, Hint, Model answer, and History tabs (the tabs shown vary by problem)

Display Settings

From the gear button (Display settings) at the top of the problem statement area, you can choose Ruby display ON / Ruby display OFF and Compact line spacing / Standard line spacing / Relaxed line spacing. Line spacing applies to the text of the problem statement, hints, and explanations; it does not change the line spacing of code or output diffs. The settings are shared with the material screen and are retained after reloading.

How to Solve

1. Open the problem from the material screen.
2. Select the programming language you want to use. If you change the language, you will be asked whether to update the editor with that language's template.
3. Write your code in the Editor tab. For problems that require submitting files, select files in the Upload tab.
4. As needed, use the Debug tab to check behavior by writing input in Standard input and pressing Run.
5. In the Submit tab, press Submit (with automatic code formatting) (or Submit).
6. When grading finishes, the results for each test case are displayed. For how to read them, see Check the Grading Results of a Problem.
7. If your answer is correct, you can move on to the next problem in the same material with Next problem.

If your answer is incorrect, you can fix it and resubmit as many times as you like. If you don't know where the error is, use the Hint.

What You Can Do in Each Tab

• Submit: Submit your code and check the grading results. During periods outside the submission window or after the deadline, hovering over the button will show a message to that effect.
• Debug: Run your code without grading. It does not count toward your submission count.
• Hint: AI points out errors in your code in progress and how to fix them. For details, see View Hints for a Coding Problem.
• Model answer: Appears for problems configured to show the model answer after the deadline. After the submission period ends, the model answer is displayed here.
• History: You can open past submissions from Submission history on server. Automatically saved in browser stores your in-progress code automatically.

Notes

• In-progress code is automatically saved in the browser. If you change PCs or browsers, or clear your browser data, it may no longer be viewable.
• Some problems prohibit copying and pasting code.
• For manually graded problems, if you pass the automatic grading, the message "Please wait for the manual grading results." is displayed. The result graded by the instructor can be checked under Manual grading result on the submission screen opened from Check Your Submissions.
• You can also check past submissions from Check Your Submissions.