Unique Paths

Question

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.

Input: m=3, n=7

Output: 28

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