class static_array():
    def __init__(self, length):
        self.ptr = []
        for _ in range(length):
            self.ptr.append(None)

    def __getitem__(self, index):
        assert 0 <= index < len(self.ptr), "The get index needs to be in range."
        return self.ptr[index]
    
    def __setitem__(self, index, value):
        assert 0 <= index < len(self.ptr), "The set index needs to be in range."
        self.ptr[index] = value

class static_array_list(static_array):
    def __init__(self, length):
        super().__init__(length)
        self.length = 0

    def __getitem__(self, index):
        assert 0 <= index < self.length, "The get index needs to be in range."
        return self.ptr[index]
    
    def __setitem__(self, index, value):
        assert 0 <= index < self.length, "The set index needs to be in range."
        self.ptr[index] = value

    def push(self,value):
        assert (self.length < len(self.ptr)), "The length before pushing has to be less than the maximum length of the array."
        self.ptr[self.length] = value
        self.length += 1

    def pop(self):
        assert (0 < self.length), "The length before popping has to be greater than 0."
        self.length -= 1
        return self.ptr[self.length]

    def unsafe_set_length(self,i):
        assert 0 <= i <= len(self.ptr), "The new length has to be in range."
        self.length = i

class dynamic_array(static_array): 
    pass

class dynamic_array_list(static_array_list):
    def length_(self): return self.length