leetcode_66. Plus One

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.

就是把这个加1了。简单

class Solution {public:    vector<int> plusOne(vector<int>& digits) {        int i = digits.size()-1;        for(i; i >=0; --i){            if(digits[i] == 9){                digits[i] = 0;            }            else{                digits[i]++;                return digits;            }        }        if(i == -1){            digits[0] = 1;            digits.push_back(0);        }                return digits;    }};