new_contents: class Solution:
      # @param    A       a list of integers
      # @param    elem    an integer, value need to be removed
      # @return an integer
      def removeElement(self, A, elem):
          result = len(A)
          start = 0
          for i in xrange(len(A)):
              A[start] = A[i]
              if A[i] != elem:
                  start += 1
              else:
                  result -= 1
          return result
  
subject: Remove Element -- keep streak!