class DiffTask(Task):

    id = 'diff'
    tests = [
        Test(id='01', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='02', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='03', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='04', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='05', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='06', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='07', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='08', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='09', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='10', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='11', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='12', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='13', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='14', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='15', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='16', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='17', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='18', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='19', time=1.0, score=5.0, dat=None, chk=None),
        Test(id='20', time=1.0, score=5.0, dat=None, chk=None),
    ]

    def load_dat(self, stream):
        N = self.read(stream, int)
        sequence = []
        for k in range(N):
            sequence.append(self.read(stream, int))
        return Dat(sequence=sequence)

    def load_chk(self, stream):
        return Chk(X=self.read(stream, int))

    def save_dat(self, stream, dat):
        self.write(stream, len(dat.sequence))
        for x in dat.sequence:
            self.write(stream, x)

    def load_sol(self, stream):
        X = self.read(stream, int)
        self.read(stream, None)
        return Sol(X=X)