https://leetcode-cn.com/problems/plus-one/description/

我的解决方案：

class Solution {
    public int[] plusOne(int[] digits) {
        //carry用来存储进位
        int carry = 0;
        int tmp = 0;
        int once=1;
        for(int i=digits.length-1;i>=0;i--) {
            tmp = digits[i]+carry+once;
            digits[i]=tmp%10;
            carry=tmp/10;
            once=0;
        }
        if(carry==1) {
            int[] res = new int[1+digits.length];
            res[0]=1;
            for(int i=0;i<digits.length;i++){
                res[i+1]=digits[i];
            }
            return res;
        }
        return digits;
    }
}