【leetcode】900. RLE Iterator

class RLEIterator(object):
    def __init__(self, A):
        """
        :type A: List[int]
        """
        self.l = A[::]

    def next(self, n):
        """
        :type n: int
        :rtype: int
        """
        while n > 0 and len(self.l) > 0:
            if self.l[0] >= n:
                self.l[0] -= n
                return self.l[1]
            else:
                n -= self.l[0]
                del self.l[0]
                del self.l[0]
                return self.next(n)
        return -1