2014 SummerTrain Beautiful Garden

#include <iostream>
#include <cstdio>
#include <map>
#include <algorithm>
#include <cstring>

using namespace std;
typedef long long LL;
const int N= 44;
int n;
LL x[N];
map<LL,int>mp;
LL gcd(LL a,LL b){return b==0?a:gcd(b,a%b);}

void run()
{
        scanf("%d",&n);
        for(int i=0;i<n;++i){
            scanf("%lld",&x[i]);
            if(mp.find( x[i] ) == mp.end() ) mp[x[i]]=1;
            else mp[x[i]]++;
        }
        if( n <= 2){ puts("0"); return ; }
        int ans=n-1;
        for(int i=0;i<n;++i){
            for(int j=i+1;j<n;++j){
                LL d=abs(x[j]-x[i]);
                if(!d){
                    ans=min(ans,n-mp[x[j]]);
                    continue;
                }
                for(int k=1;k<=n-1;++k){
                    LL g=gcd((LL)k,d);
                    LL c=min(x[i],x[j]);
                    LL dis=k/g;
                    LL d2=d/g;
                    int cnt=0;
                    for(int z=0; z < n; z += dis){           //dis~~
                        if(mp.find(c) != mp.end()) cnt++;
                        c += d2;
                    }
                    ans = min(ans,n-cnt);
                }
            }
        }
        printf("%d\n",ans);
}

int main()
{
    //freopen("in.txt","r",stdin);
    int cas=1,_;
    scanf("%d",&_);
    while(_--){    
                mp.clear();
        printf("Case #%d: ",cas++);
        run();    
    }
    return 0;
}