63 leetcode - Unique Paths

#!/usr/bin/python# -*- coding: utf-8 -*-'''Unique PathsA 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?'''class Solution(object):    def uniquePaths(self, m, n):        """        :type m: int        :type n: int        :rtype: int        """        if m == 0 or n == 0:            return 0        dp = [[0] * n  for i in range(m)]        for i in range(n):            dp[0][i] = 1        for i in range(m):            dp[i][0] = 1        for row in range(1,m):            for col in range(1,n):                dp[row][col] = dp[row - 1][col] + dp[row][col - 1]        return dp[m-1][n-1]if __name__ == "__main__":    s = Solution()    print s.uniquePaths(2,2)