【LeetCode】66 - Plus One

Given a non-negative number represented as an array of digits, plus one to the number.

The digits are stored such that the most significant digit is at the head of the list.

Solution 1 : 十进制加法

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

Solution 2 ：

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