LeetCode-66.Plus One

https://leetcode.com/problems/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.

public int[] PlusOne(int[] digits)        {            int n = digits.Length,i = 0;            int[] res;            while (i < n)            {                if (digits[i] != 9)                    break;                i++;            }            if (i==n)            {                res = new int[n + 1];                res[0] = 1;                return res;            }            res = digits;            for (i = n-1; i >=0; i--)            {                if (digits[i] == 9)                {                    res[i] = 0;                }                else                {                    res[i] += 1;                    return res;                }            }            return res;        }

优化一下

 public int[] PlusOne(int[] digits)        {            int n = digits.Length;            int[] res = digits;            for (int i = n - 1; i >= 0; i--)            {                if (digits[i] == 9)                {                    res[i] = 0;                }                else                {                    res[i] += 1;                    return res;                }            }            res = new int[n + 1];            res[0] = 1;            return res;        }