Easy cpp approach:-

vector jimOrders(vector> orders) {

int n=orders.size();

vector<int>dt(n,0);
vector<int>cid(n,0);



for (int i=0;i<n;i++)
{
    dt[i]= orders[i][1]+orders[i][0];
    cid[i]=i+1;
}

for (int i=0;i<n-1;i++)
{
    for (int j=0;j<n-i-1;j++)
    {
        if (dt[j]>dt[j+1])
        {
            swap(dt[j],dt[j+1]);
            swap(cid[j],cid[j+1]);
        }
    }
}

return cid;

}****