leetcode -- Plus One

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

 1 public class Solution {
 2     public int[] plusOne(int[] digits) {
 3         // Start typing your Java solution below
 4         // DO NOT write main() function
 5         int len = digits.length;
 6         digits[len - 1] += 1;
 7         int carry = 0;
 8         for(int i = len - 1; i >= 0; i --){
 9             digits[i] += carry;
10             carry = 0;
11             if(digits[i] >= 10){
12                 carry = digits[i] / 10;
13                 digits[i] %= 10;
14             }
15         }
16         if(carry > 0){
17             int[] result = new int[len + 1];
18             result[0] = carry;
19             for(int i = 0; i < len; i++){
20                 result[i + 1] = digits[i];
21             }
22             return result;
23         } else {
24             return digits;
25         }
26     }
27 }

carry加完后需重置为0，因为后面只会有进位的时候才会重新计算carry