Artifact ae835c90175ffde078c8203e8e698cf3c8d524dc
#include <iostream>
#include <sstream>
#include <iomanip>
#include <vector>
using namespace std;
static const unsigned MODVAL = 1000000007;
struct mint
{
unsigned val;
mint():val(0){}
mint(int x):val(x%MODVAL) {}
mint(unsigned x):val(x%MODVAL) {}
};
mint& operator+=(mint& x, mint y) { return x = x.val+y.val; }
class AlienAndSetDiv1 { public:
int getNumber(int N, int K)
{
memo.assign((1<<K)*(N+1)*(N+1), -1);
vector<int> A, B;
return rec(N, K, A, B, 0);
}
vector<int> memo;
int rec(size_t N, int K, vector<int>& A, vector<int>& B, int lastk)
{
if(A.size()==N && B.size()==N)
return 1;
auto key = (lastk*(N+1)+A.size())*(N+1)+B.size();
if(memo[key] >= 0)
return memo[key];
int next = A.size()+B.size()+1, nextmask = (lastk &~ (1<<(K-1)))<<1;
int ai = A.size(), bi = B.size();
mint total = 0;
A.push_back(next);
if(A.size()<=N && (ai>=B.size() || abs(A[ai]-B[ai])>=K))
total += rec(N, K, A, B, nextmask);
A.pop_back();
B.push_back(next);
if(B.size()<=N && (bi>=A.size() || abs(A[bi]-B[bi])>=K))
total += rec(N, K, A, B, nextmask|1);
B.pop_back();
return memo[key] = total.val;
}
};
// 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 int& Expected, const int& 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(_, AlienAndSetDiv1().getNumber(N, K));}
int main(){
CASE(0)
int N = 2;
int K = 2;
int _ = 2;
END
CASE(1)
int N = 3;
int K = 1;
int _ = 20;
END
CASE(2)
int N = 4;
int K = 2;
int _ = 14;
END
CASE(3)
int N = 10;
int K = 7;
int _ = 40;
END
CASE(4)
int N = 50;
int K = 10;
int _ = -1;
END
CASE(5)
int N = 50;
int K = 1;
int _ = -1;
END
CASE(5)
int N = 50;
int K = 2;
int _ = -1;
END
CASE(5)
int N = 50;
int K = 4;
int _ = -1;
END
CASE(5)
int N = 2;
int K = 2;
int _ = 2;
END
}
// END CUT HERE