# Leetcode 62. Unique Paths # Question Description

Original Question: Leetcode 62. Unique Paths

A robot is located at the top-left corner of a m x n grid (marked 'Start' in the diagram below).

The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked 'Finish' in the diagram below).

How many possible unique paths are there?

### Example 1:​

Input: m = 3, n = 2Output: 3Explanation:From the top-left corner, there are a total of 3 ways to reach the bottom-right corner:1. Right -> Right -> Down2. Right -> Down -> Right3. Down -> Right -> Right

### Example 2:​

Input: m = 7, n = 3Output: 28

# Solution

class Solution {    public int uniquePaths(int m, int n) {        if(m == 0|| n==0) return 0;        int[][] dp = new int[m][n];        for(int i = 0; i < m; i++){            dp[i][n-1] = 1;        }        for(int i = 0; i < n; i++){            dp[m-1][i] = 1;        }        for(int j = m-2; j>=0; j--){            for(int i = n-2; i>=0;i--){                dp[j][i] = dp[j+1][i] + dp[j][i+1];            }        }        return dp;    }}