Time: 0:00
Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).
This bug belongs to the off-by-one errors pattern
The loop that runs one time too many, the slice that drops the last item, the index that starts in the wrong place.
What went wrong: the loop runs len(grid) times, which is the number of rows (2). It should run once per column (3).
The fix: for i in range(len(grid[0]))
Remember: test grids that are not square.
The pattern behind it: off-by-one errors.
Paste this into any web page or blog post. Visitors fix the bug right there, in their browser.
<iframe src="https://trybughunt.com/embed/413f23e4-601e-43e3-85a7-d6bd375f2729" title="Debugging challenge: Swapping rows and columns drops a column" width="100%" height="580" loading="lazy" style="border:1px solid #d4d4d8;border-radius:12px;max-width:760px"></iframe>
<p style="font-size:14px">Debugging challenge from <a href="https://trybughunt.com/challenges/413f23e4-601e-43e3-85a7-d6bd375f2729">TryBugHunt</a></p>