#303 Count Paths

Given a grid of size m x n, count the number of unique paths from top-left to bottom-right corner.

Rules:

• Can only move right or down at each step
• Must reach bottom-right corner
• All paths must be unique
• Result will fit in 32-bit integer

Constraints:

• 1 ≤ m, n ≤ 100

Examples:

// Example 1:
console.log(uniquePaths(3, 6));
// Output: 21
// Explanation: 21 different ways to reach bottom-right

// Example 2:
console.log(uniquePaths(3, 3));
// Output: 6
// Explanation: 6 different ways in 3x3 grid