Artifact 66d130730b42345ebe1bd3c04a80608706a51daf
#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <numeric>
#include <iterator>
#include <functional>
#include <complex>
#include <queue>
#include <stack>
#include <cmath>
#include <cassert>
#include <cstring>
using namespace std;
typedef long long LL;
typedef complex<double> CMP;
class TheHexagonsDivOne { public:
long long count(int n)
{
// at least there must be 7<=2*n numbers...
if( n <= 3 )
return 0;
// center hex has 2n possibility
// choose others from 2(n-1) candidates
// normalize by /6 to classify by the least number
LL ans = 0;
vector<int> pat;
count_pat( pat, n-1, ans );
return ans*2*n/6;
}
void count_pat( vector<int>& pat, LL n, LL& ans )
{
int i = pat.size();
if( i == 6 )
{
LL distinct = set<int>(pat.begin(), pat.end()).size();
LL tmp = 1;
for(int d=0; d<distinct; ++d)
tmp *= (n-d);
LL dup = 6 - distinct;
for(int d=0; d<dup; ++d)
tmp *= 2;
LL nodup = 6 - 2*dup;
for(int d=0; d<nodup; ++d)
tmp *= 2;
ans += tmp;
return;
}
vector<int> use(7);
int next = 1;
for(int k=0; k<pat.size(); ++k) {
use[pat[k]]++;
next = max(next, pat[k]+1);
}
if( next <= n )
{
pat.push_back(next);
count_pat( pat, n, ans );
pat.pop_back();
}
for(int p=1; p<next; ++p)
if( use[p]<=1 )
if( i==0 || (pat[i-1]!=p && (i<5 || pat[0]!=p)) )
{
pat.push_back(p);
count_pat( pat, n, ans );
pat.pop_back();
}
}
};
// BEGIN CUT HERE
#include <ctime>
double start_time; string timer()
{ ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v)
{ os << "{ ";
for(typename vector<T>::const_iterator it=v.begin(); it!=v.end(); ++it)
os << '\"' << *it << '\"' << (it+1==v.end() ? "" : ", "); os << " }"; return os; }
void verify_case(const long long& Expected, const long long& Received) {
bool ok = (Expected == Received);
if(ok) cerr << "PASSED" << timer() << endl; else { cerr << "FAILED" << timer() << endl;
cerr << "\to: \"" << Expected << '\"' << endl << "\tx: \"" << Received << '\"' << endl; } }
#define CASE(N) {cerr << "Test Case #" << N << "..." << flush; start_time=clock();
#define END verify_case(_, TheHexagonsDivOne().count(n));}
int main(){
CASE(0)
int n = 3;
long long _ = 0LL;
END
CASE(1)
int n = 4;
long long _ = 256LL;
END
CASE(2)
int n = 8;
long long _ = 3458560LL;
END
CASE(3)
int n = 20;
long long _ = 11193888000LL;
END
CASE(4)
int n = 1;
long long _ = 0LL;
END
CASE(5)
int n = 150;
long long _ = -1LL;
END
}
// END CUT HERE