62. Unique Paths ( JAVA ) leetcode

class Solution {
    public int uniquePaths(int m, int n) {
        
        int [][] grid = new int[m][n];

        for(int i = 0; i < m; i++) {
            grid[i][0] = 1;
        }
    
        for(int i = 0; i < n; i++) {
            grid[0][i] = 1;
        }

        for(int i = 1; i < m ; i++) {
            for(int j = 1; j < n; j++) {
                grid[i][j] = grid[i-1][j] + grid[i][j-1];
            }
        }
        
        return grid[m-1][n-1];
    }
}