LightOj 1014 - Ifter Party

 // Accepted
#include <iostream>
#include <cstdio>
#include <cstring>
#include <map>
#include <string>
#include <vector>
#include <cmath>
#include <cctype>
#include <sstream>
#include <set>
#include <list>
#include <stack>
#include <queue>
#include <algorithm>
#define sf scanf
#define pf printf
#define sfint scanf ("%d %d",&a,&b)
#define sfl scanf ("%ld %ld",&a,&b)
#define sfll scanf ("%lld %lld",&a,&b)
#define sfd scanf ("%lf %lf",&a,&b)
#define sff scanf ("%f %f",&a,&b)
#define lp1(i,n) for(i=0;i<n;i++)
#define lp2(i,n) for(i=1;i<=n;i++)
#define LL long long
#define L long
#define mem(c,v) memset(c,v,sizeof(c))
#define ui unsigned int
#define ull unsigned long long int
#define ul unsigned long
#define nl puts("")
#define sq(x) ((x)*(x))
#define MX 1000005
#define N 100
#define MOD 10000000007
#define pb push_back
#define pi acos(-1.0)
#define sz size()
#define gc getchar ()
#define ps push
#define clr clear
#define inf 2147483647
#define bn begin()
#define ed end()

using namespace std;

int main()
{
    int t,tc=1;
    vector<ull>v;

    sf("%d",&t);

    while(t-- and tc++)
    {
        ull p,q,l,modu,divd;

        sf("%llu %llu",&p,&l);

        if(p<l)
        {
            p=p^l;
            l=l^p;
            p=p^l;
        }

//        if(!l)
//        {
//            v.push_back(1);
//        }

        q = p-l;

        pf("Case %d:",tc-1);

        if(q<=l)
        {
            pf(" impossible\n");
        }

        else {

        //v.push_back(q);

        ull k = sqrt(q),i; //cout << k;

        for(i=1;i<=k;i++)
        {
            modu=q%i;

            if(!modu)
            {
                divd=q/i;

                if(divd > l)
                {
                    v.push_back(divd);
                }

                if(i>l and divd!=i)
                {
                   v.push_back(i);
                }
            }
        }

        sort(v.begin(),v.end());

        ull vlen=v.size(),sp=vlen;

        for(i=0;i<vlen;i++)
        {
            pf(" %llu",v[i]);
//            if(sp>1)
//            {
//                pf(" ");
//                sp--;
//            }
        }

        v.clear();
        nl;
    }

    }

    return 0;
}