66、plusOne
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.
题目:给定一个非负int型数组,返回这个数组加1后的int型数组。并且返回的int型数组不包含以0为开头。