【LeetCode】066. 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.

题解：

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