Solving Coding Problems

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

Screen Layout

The problem screen is divided into three areas from left to right. Use the button in the upper right of each area to collapse or restore that area.

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

Display Settings

From the gear button (Display Settings) at the top of the problem statement area, you can choose Ruby Display ON or Ruby Display OFF, and Compact Line Spacing, Standard Line Spacing, or Spacious 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 kept 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 the template for that language.
3. Write your code in the Editor tab. For problems that require submitting a file, choose the file in the Upload tab.
4. If needed, use the Debug tab to enter input in Standard Input, press Run, and check the behavior.
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 Checking Problem Judge Results.
7. If your answer is correct, you can use Next Problem to move on to the next problem in the same material.

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 Hints.

What You Can Do in Each Tab

• Submit: Submit your code and check the grading results. Outside the submission period or after the deadline, hovering over the button shows a message to that effect.
• Debug: Runs your code without grading. It does not count toward the submission count.
• Hint: AI points out the errors in your in-progress code and how to fix them. For details, see Viewing Hints for Coding Problems.
• Model Answer: Shown for problems set to display the model answer after the deadline. After the submission period ends, the model answer appears here.
• History: You can open past submissions from Server Submission History. Browser Auto-Save automatically saves your in-progress code.

Notes

• In-progress code is automatically saved in your browser. If you change PCs or browsers, or clear your browser data, it may no longer be displayed.
• For some problems, copying and pasting code is prohibited.
• For problems graded manually, if your answer passes automatic grading, the message "Please wait for the manual grading results." is displayed. The results graded by the instructor can be viewed in Manual Grading Result on the submission screen opened from Checking Your Submissions.
• You can also check past submissions from Checking Your Submissions.