UVa 10880 - Colin and Ryan Solution

#include<iostream>
#include<list>
#include<string>
#include<cstring>
#include<sstream>
#include<cctype>
#include<string.h>
#include<algorithm>
#include<cmath>
#include<stack>
#include<fstream>
#include<cstdlib>
#include<vector>
#include<map>
#include<set>
#include<utility>
#include<iomanip>
#include<queue>

using namespace std;

#define INF (1<<29)
#define SET(a) memset(a,-1,sizeof(a))
#define ALL(a) a.begin(),a.end()
#define CLR(a) memset(a,0,sizeof(a))
#define FILL(a,v) memset(a,v,sizeof(a))
#define PB push_back
#define FOR(i,n) for(int i = 0;i<n;i++)
#define PI acos(-1.0)
#define EPS 1e-9
#define MP(a,b) make_pair(a,b)
#define min3(a,b,c) min(a,min(b,c))
#define max3(a,b,c) max(a,max(b,c))
#define READ(f) freopen(f, "r", stdin)
#define WRITE(f) freopen(f, "w", stdout)
#define LL long long
#define MX 100000
#define MOD 1000000007




int main()
{
    LL t,kk=1,c,r,sqt,i,num;
    cin>>t;
    while(t--)
    {
        cin>>c>>r;
        if(c==r)
        {
            cout<<"Case #"<<kk++<<": 0"<<endl;
            continue;
        }
        set<LL>ans;
        set<LL>:: iterator it;
        num=c-r;
        sqt=sqrt(num);
        for(i=1;i<=sqt;i++)
        {
            if(num%i==0)
            {
                if(i>r)
                ans.insert(i);
                if((num/i)>r)
                ans.insert(num/i);
            }
        }
        cout<<"Case #"<<kk++<<":";
        for(it=ans.begin();it!=ans.end();it++)
        cout<<" "<<*it;
        cout<<endl;
    }

return 0;
}