# LeetCode — Unique Paths(Blind Curated 25)

There is a robot on an `m x n`

grid. The robot is initially located at the **top-left corner** (i.e., `grid[0][0]`

). The robot tries to move to the **bottom-right corner** (i.e., `grid[m - 1][n - 1]`

). The robot can only move either down or right at any point in time.

Given the two integers `m`

and `n`

, return *the number of possible unique paths that the robot can take to reach the bottom-right corner*.

The test cases are generated so that the answer will be less than or equal to `2 * 109`

.

**Example 1:**

`Input: m = 3, n = 7`

Output: 28

**Example 2:**

`Input: m = 3, n = 2`

Output: 3

Explanation: From the top-left corner, there are a total of 3 ways to reach the bottom-right corner:

1. Right -> Down -> Down

2. Down -> Down -> Right

3. Down -> Right -> Down

**Constraints:**

`1 <= m, n <= 100`

Solution:

Time complexity: O(N * M)

Space complexity: O(N * M)