CodingMediumcod-p031

Subject Dynamic programmingLevel Mid–Senior~25 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

A robot at the top-left of an m x n grid can only move right or down. Return the number of distinct paths to the bottom-right.

Implement

unique_paths(m: int, n: int) → int

Examples

in[3,7]out28

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.