Unique Paths in 2D grid

Problem : There is an m x n grid. One can only move either down or right at any point in time. One is trying to reach the bottom-right corner of the grid. How many possible unique paths are there? (project euler problem 15) The similar question has been asked in Cracking the coding interview: Here we have to count the unique paths, but there we have to find the unique paths. [Read More]