[leetcode] 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.

思路：将加一的结果先逆序存在vector中，最高位进位如果为1则vector中再push_back一个1，然后将vector反转即得到结果

代码：

class Solution {
public:
vector<int> plusOne(vector<int> &digits) {
int len=digits.size();
vector<int> res;
if(len==0) return res;
int add=0;
for(int i=len-1;i>=0;i--){
if(i==len-1){
res.push_back((digits[i]+1+add)%10);
add=(digits[i]+1+add)/10;
}
else{
res.push_back((digits[i]+add)%10);
add=(digits[i]+add)/10;
}
}
if(add!=0) res.push_back(1);
reverse(res.begin(),res.end());
return res;
}
};