66. Plus One

 1 class Solution {
 2 public:
 3     vector<int> plusOne(vector<int>& digits) {
 4         int carry = 1;
 5         
 6         for(int i = digits.size()-1; i >= 0; i--){
 7             int sum = digits[i] + carry;
 8             carry = sum/10;
 9             digits[i] = sum % 10;
10             if(carry == 0){
11                 break;
12             }
13         }
14         
15         if(carry == 1){
16             digits.insert(digits.begin(), 1);
17         }
18         
19         return digits;
20     }
21 };