题目：

Given a non-negative integer represented as a non-empty array of digits, plus one to the integer.

You may assume the integer do not contain any leading zero, except the number 0 itself.

The digits are stored such that the most significant digit is at the head of the list.

给一个整数序列+1，输出序列

class Solution(object):
    def plusOne(self, digits):
        “””
        :type digits: List[int]
        :rtype: List[int]
        “””
        l = len(digits);n=1
        for i in range(l):
            s = digits[l-i-1]+n
            digits[l-i-1] = s%10;n=s/10
        if n>0:digits.insert(0,n)
        return digits