66. Plus One 难度：easy

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.

思路：

遍历数组的每位，同时处理进位，如果最后还有进位，则在数组最前面在插入1即可。

程序：

class Solution {public:    vector<int> plusOne(vector<int>& digits) {         int c = 1;          for(int i = digits.size() - 1; i >= 0; -- i)         {            int a = digits[i] + c;            digits[i] = a % 10;            c = a / 10;         }         if(c == 1)             digits.insert(digits.begin(), 1);                 return digits;    }};