(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.

大数字加法，一开始以为只是简单地整数加法，后来才发现是大数字

class Solution {
public:
vector<int> plusOne(vector<int>& digit){
//         int len = digit.size();
//         long long res = 0;
//         reverse(digit.begin(),digit.end());
//         for(int j = len-1;j >= 0;--j)
//         {
//             res = res*10+ digit[j];
//         }
//         long long newres = res+1;
//         digit.clear();
//         while(newres!=0)
//         {
//             int a = newres%10;
//             digit.push_back(a);
//             newres /= 10;
//         }
//         reverse(digit.begin(),digit.end());
//         return digit;

int carry = 0;
//reverse(digit.begin(),digit.end());
vector<int> newvec;
int len = digit.size();
for(int i=len-1;i>=0;--i)
{
int tmp;
if(i == len-1)
{
tmp = digit[i] + 1;
}
else
tmp = digit[i] + carry;

carry = 0;

if(tmp>=10)
{
carry = 1;
tmp=tmp%10;
newvec.push_back(tmp);
}
else
{
newvec.push_back(tmp);
}

if(i == 0 && carry == 1)
{
newvec.push_back(carry);
}
}
reverse(newvec.begin(),newvec.end());
return newvec;
}
};