[leetcode DP]62.Unique Paths

判断一个物体从左上角到右下角有多少种走法

 class Solution(object):
     def uniquePaths(self, m, n):
         flag = [[1 for j in range(n)] for i in range(m)]
         for i in range(1,m):
             for j in range(1,n):
                 flag[i][j] = flag[i-1][j] + flag[i][j-1]
         return flag[-1][-1]