new_contents: # 393. UTF-8 Validation 
  
  # A character in UTF8 can be from 1 to 4 bytes long, subjected to the following rules:
  
  #     For 1-byte character, the first bit is a 0, followed by its unicode code.
  #     For n-bytes character, the first n-bits are all one's, the n+1 bit is 0, followed by n-1 bytes with most significant 2 bits being 10.
  
  # This is how the UTF-8 encoding would work:
  
  #    Char. number range  |        UTF-8 octet sequence
  #       (hexadecimal)    |              (binary)
  #    --------------------+---------------------------------------------
  #    0000 0000-0000 007F | 0xxxxxxx
  #    0000 0080-0000 07FF | 110xxxxx 10xxxxxx
  #    0000 0800-0000 FFFF | 1110xxxx 10xxxxxx 10xxxxxx
  #    0001 0000-0010 FFFF | 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
  
  # Given an array of integers representing the data, return whether it is a valid utf-8 encoding.
  
  # Note:
  # The input is an array of integers. Only the least significant 8 bits of each integer is used to store the data. This means each integer represents only 1 byte of data.
  
  # Example 1:
  
  # data = [197, 130, 1], which represents the octet sequence: 11000101 10000010 00000001.
  
  # Return true.
  # It is a valid utf-8 encoding for a 2-bytes character followed by a 1-byte character.
  
  # Example 2:
  
  # data = [235, 140, 4], which represented the octet sequence: 11101011 10001100 00000100.
  
  # Return false.
  # The first 3 bits are all one's and the 4th bit is 0 means it is a 3-bytes character.
  # The next byte is a continuation byte which starts with 10 and that's correct.
  # But the second continuation byte does not start with 10, so it is invalid.
  
  class Solution(object):
      def validUtf8(self, data):
          """
          :type data: List[int]
          :rtype: bool
          """
          i = 0
          while i < len(data):
              try:
                  length = bin(data[i])[2:].zfill(8).index('0')
                  # print("Length is " + str(length))
              except:
                  # print("not containing 0")
                  return False
              
              if length == 0: # 1-byte 
                  i += 1
              elif length in [2, 3, 4]: # 2, 3, 4 byte
                  for j in range(length - 1):
                      # print(i+j+1)
                      try:
                          if bin(data[i + j + 1])[2:].zfill(8).index('0') != 1:
                              return False
                      except:
                          return False
                  i += length
              else:
                  return False
          return True
subject: add 393