题目:
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.
思路:
这题比较简单,注意几个边界条件就行。
1)数组低位代表数字的高位
2)最后如果还有进位,则需增加一位最高位1
实现如下:
class Solution {
public:
vector<int> plusOne(vector<int>& digits) {
int size = digits.size();
if (size < 1) return digits;
int flag = 0;
if (digits[size - 1] > 8)
{
flag = 1;
digits[size - 1] = digits[size - 1] - 9;
}
else
{
digits[size - 1] += 1;
return digits;
}
for (int i = size - 2; i >= 0; --i)
{
if (i>0 && flag == 0) break;
if (digits[i] > 8)
{
flag = 1;
digits[i] = digits[i] - 9;
}
else
{
digits[i] += flag;
flag = 0;
}
}
if (flag == 1) digits.insert(digits.begin(), 1);
return digits;
}
};