Unique Paths in Grid

Problem

Count paths from the top-left to bottom-right of an m by n grid, moving only right or down.

Examples

Example 1

Input: {"m":3,"n":7}

Output: 28

Example 2

Input: {"m":1,"n":5}

Output: 1

Input and output use JSON-compatible values. For linked-list and tree questions, arrays represent the node structure as described above. Your code should implement solve(input).

Write your solutionImplement solve(input). Your draft is saved in this browser.

Compiler

How to solve Unique Paths in Grid

Count paths from the top-left to bottom-right of an m by n grid, moving only right or down. Paths to a cell are the sum of paths from above and left. The reference implementation illustrates this approach; check the example and edge cases.

Time and space complexity

O(mn) time and O(n) space.

Practise and improve

Choose JavaScript, TypeScript or Python, complete the starter code, then select Run Tests. Request a hint when you need guidance, or choose View solution and confirm if you would like to study the reference implementation.