【LeetCode & 剑指offer刷题】数组题18：Plus One
【LeetCode & 剑指offer 刷题笔记】目录（持续更新中...）
Plus One
Given a non-empty array of digits representing a non-negative integer, plus one to the integer.
The digits are stored such that the most significant digit is at the head of the list, and each element in the array contain a single digit.
You may assume the integer does not contain any leading zero, except the number 0 itself.
Example 1:
Input: [1,2,3]
Output: [1,2,4]
Explanation: The array represents the integer 123.
Example 2:
Input: [4,3,2,1]
Output: [4,3,2,2]
Explanation: The array represents the integer 4321.
/*
问题：数组加一，高位在前，低位在后
要考虑进位情况
*/
class Solution
{
public:
vector<int> plusOne(vector<int>& digits)
{
for(int i = digits.size()-1; i>=0; i--) //从后往前扫描
{
if(digits[i] == 9) digits[i] = 0; //如果为9，置0，下次进位
else
{
digits[i]++;
return digits; //不为9就加一，退出
}
}
digits[0] = 1; //如果最高位有进位，置1
digits.push_back(0); //补充一位
return digits;
}
};
