(LightOj) 1014 – Ifter Party

Note the looping style for finding divisors. It’s the perfect way! Don’t try otherwise, or you will get Wrong divisors for 2.

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#include<bits/stdc++.h>


#define FOR(i, s, e) for(int i=s; i<e; i++)
#define loop(i, n) FOR(i, 0, n)
#define sf scanf
#define pf printf
#define pb push_back
#define MP make_pair
#define fr first
#define sc second
#define ll long long
#define dd double
#define all(v) v.begin(), v.end()
#define PI acos(-1.0)
#define mem(ara, value) memset(ara, value, sizeof(ara))
#define paii pair<int, int>
#define pall pair<ll, ll>
#define SZ(a) int(a.size())
#define read(nm) freopen(nm, "r", stdin)
#define write(nm) freopen(nm, "w", stdout)

#define take(args...) asdf,args
#define dump(x) cerr<<#x<<" = "<<x<<endl
#define debug(args...) cerr,args; cerr<<endl;
using namespace std;


template<typename T>
ostream& operator<<(ostream& output, vector<T>&v)
{
    output<<"[ ";
    if(SZ(v))
    {
        output<<v[0];
    }
    FOR(i, 1, SZ(v))
    {
        output<<", "<<v[i];
    }
    output<<" ]";
    return output;
}

template<typename T1, typename T2>
ostream& operator<<(ostream& output, pair<T1, T2>&p)
{
    output<<"( "<<p.fr<<", "<<p.sc<<" )";
    return output;
}




template<typename T>
ostream& operator,(ostream& output, T x)
{
    output<<x<<" ";
    return output;
}



struct ASDF{
    ASDF& operator,(int &a) {
        sf("%d", &a);
        return *this;
    }
    ASDF& operator,(long int &a){
        sf("%ld", &a);
        return *this;
    }
    ASDF& operator,(long long int &a){
        sf("%lld", &a);
        return *this;
    }
    ASDF& operator,(char &c){
        sf("%c", &c);
        return *this;
    }
    ASDF& operator,(double &d){
        sf("%lf", &d);
        return *this;
    }

    template<typename T>
    ASDF& operator,(T &a){
        cin>>a;
        return *this;
    }
}asdf;



//Header ends here

ll P, L;
//vector<ll>choto, boro;

vector<ll> result;

int main()
{

    int kases, kaseno = 0;

    sf("%d", &kases);

    while(kases--)
    {
        sf("%lld %lld", &P, &L);

        ll N = P - L;

        ll root = sqrt(N);

        result.clear();

        //ll till = max(L, root);


        for(ll q = 1; q<=root; q++)
        {
            if( (N%q) == 0)
            {
                if(q > L)
                {
                    result.pb(q);
                }

                if( (q*q != N) && (N/q) > L)
                {
                    result.pb(N/q);
                }

            }
        }

        //dump(result);

        sort(all(result));


        pf("Case %d:", ++kaseno);

        if(SZ(result))
        {
            loop(i, SZ(result))
            {
                pf(" %lld", result[i]);
            }
            pf("\n");
        }
        else
        {
            pf(" impossible\n");
        }



    }



    return 0;
}