66. Plus One

原题

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

You may assume the integer do not contain any leading zero, except the number 0 itself.

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

代码实现

 public int[] PlusOne(int[] digits)     {        int index = digits.Length - 1;        if(digits[index]<9)          {              digits[index]++;              return digits;          }        if(index==0) return new int[]{1,0};         int i = index;        while(digits[i]==9)        {            digits[i] = 0; //位溢出            if(i==0) //所有的位溢出            {                int [] rtn = new int[index+2];                rtn[0]=1;                return rtn;            }            i--;        }        digits[i]++; //第i位不为9（i > 0）        return digits;    }