class RingBuffer():
    """
    I stole this (with permission)
    """
    def __init__(self, max_length, reactivity_factor=10):
        self.max_length = max_length
        self.index = 0
        self.rb = []
        self.intermed = []
        self.reactivity_factor = reactivity_factor

    def add(self, x):
        if len(self.rb) < self.max_length:
            self.rb.append(x)
            self.index += 1
        else:
            if len(self.intermed) < self.__stability():
                self.intermed.append(x)
            else:
                x = sum(self.intermed) / len(self.intermed)
                if self.index >= self.max_length:
                    self.index = 0
                self.rb[self.index] = x
                self.index += 1
                self.intermed.clear()

    def __stability(self):
        if self.reactivity_factor > self.max_length:
            self.reactivity_factor = self.max_length
        return (int)(self.max_length / self.reactivity_factor)

    def clear(self):
        self.rb = []
        self.index = 0

    def avg(self):
        return sum(self.rb) / len(self.rb)