第三题这样子正确吗

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
int ispalindrome(vector<int> &a);
int main()
{
    int n;
    cin>>n;
    int i=0;
    int sum=0;
    for(i=0;i<=n;i++)
    {
        vector<int> vv;
        int t=i;
        int s=0;
        if(i==0)
            sum=sum+1;
        else
        {
            while(t)
            {
                s=t%2;
                vv.push_back(s);
                t=t/2;            
            }
            sum=sum+ispalindrome(vv);
        }        
    }
    cout<<sum<<endl;
    return 0;
}
int ispalindrome(vector<int> &a)
{
    int i=0,j=a.size()-1;
    for(i=0,j=a.size()-1;i<j;i++,j--)
    {
        if(a[i]!=a[j])
            return 0;
    }
    return 1;
}