The Wide View
A hard Python mock interview question on DataDriven. Practice with AI-powered feedback, real code execution, and a hire/no-hire decision.
- Domain
- Python
- Difficulty
- hard
- Seniority
- L4
Interview Prompt
A reporting export arrives in long format: one record per cell, each carrying a `row` label, a `col` label, and a numeric `val`. Reshape it into a nested lookup keyed by row then column, so `result[row][col]` returns that cell's value. Rows are sparse, holding only the columns that actually appear for them, and when the same row and column pair shows up more than once the later record wins.
Summary
Long format is easy. Wide format is useful.
How This Interview Works
- Read the vague prompt (just like a real interview)
- Ask clarifying questions to the AI interviewer
- Write your python solution with real code execution
- Get instant feedback and a hire/no-hire decision