import itertools as it

class MyPolynomial(object):
  def __init__(self, *coefficients):
    self.coefficients = list(coefficients)
    self._priv = None

  def __eq__(self, y):
    return str(self) == str(y)


  def __repr__(self):
    if len(self.coefficients) == 0:
      return '{}({})'.format(
        self.__class__.__name__, '0'
        )
    if sum(self.coefficients) == 0:
      return '{}({})'.format(
        self.__class__.__name__, '0'
        )
    return '{}({})'.format(
      self.__class__.__name__, ', '.join((str(x) for x in self.coefficients))
      )

  def __add__(self, other):
    n = len(self.coefficients)
    p = len(other.coefficients)
    if (n >= p):
      new_coefficients = [self.coefficients[i] for i in range(n)]
      for i in range(p):
        new_coefficients[i] += other.coefficients[i]
    if (p >= n):
      new_coefficients = [other.coefficients[i] for i in range(p)]
      for i in range(n):
        new_coefficients[i] += self.coefficients[i]
    return MyPolynomial(*new_coefficients)

  def __iadd__(self, other):
    for i, x in enumerate(self.coefficients):
      self.coefficients[i] += other.coefficients[i]
    return self

  def __str__(self):
    out = ''
    size = len(self.coefficients)
    for i in range(size):
        if self.coefficients[i] != 0:
            out += ' + %gx^%d' % (self.coefficients[i],i)

    out = out.replace('+ -', '- ')
    out = out.replace('x^0', '1')
    out = out.replace(' 11 ', ' 1 ')
    if out[0:3] == ' + ':
        out = out[3:]
    if out[0:3] == ' - ':
        out = '-' + out[3:]
    if len(out) == 0:
      return '0'
    return out

  def from_iterable(iterables):
    return MyPolynomial(*iterables)

  def degree(self):
    if len(self.coefficients) == 0:
      return 0
    if sum(self.coefficients) == 0:
      return 0
    i = 1
    iterator = len(self.coefficients)-1
    print("iter:"+str(iterator))
    for x in self.coefficients:
      if self.coefficients[iterator] == 0:
        i = i + 1
      else:
        break
      iterator = iterator - 1
    return len(self.coefficients) - i


print(repr(MyPolynomial(2)+MyPolynomial(3,4)))
assert MyPolynomial(5, 8) == MyPolynomial(2, 4) + MyPolynomial(3, 4)

mp1 = MyPolynomial(2, 4)
mp2 = MyPolynomial(3, 4)
mp3 = MyPolynomial(5, 8)
mp1 += mp2
assert mp3 == mp1