new_contents: class Solution:
      # @param num, a list of integer
      # @return an integer
  
      def rob(self, num):
          res1 = res2 = 0
          for n in num:
              res1, res2 = res2+n, max(res1, res2)
          return max(res1, res2)
  
subject: add solution for House Robber