CodingEasycod-g401

Subject MathLevel Entry–Mid~15 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given an Excel-style column title (a string of uppercase letters A-Z, e.g. 'A', 'Z', 'AA', 'AB', ... 'ZY'), return its corresponding 1-based column number. A=1, Z=26, AA=27, AB=28, and so on. The title has length 1 to 7. This is bijective base-26 (there is no zero digit).

Implement

excel_col_number(s: str) → int

Examples

in["A"]out1

What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

Learn the concepts

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.