4fd800b3a8 2011-02-23        kinaba: #include <iostream>
4fd800b3a8 2011-02-23        kinaba: #include <sstream>
4fd800b3a8 2011-02-23        kinaba: #include <iomanip>
4fd800b3a8 2011-02-23        kinaba: #include <vector>
4fd800b3a8 2011-02-23        kinaba: #include <string>
4fd800b3a8 2011-02-23        kinaba: #include <map>
4fd800b3a8 2011-02-23        kinaba: #include <set>
4fd800b3a8 2011-02-23        kinaba: #include <algorithm>
4fd800b3a8 2011-02-23        kinaba: #include <numeric>
4fd800b3a8 2011-02-23        kinaba: #include <iterator>
4fd800b3a8 2011-02-23        kinaba: #include <functional>
4fd800b3a8 2011-02-23        kinaba: #include <complex>
4fd800b3a8 2011-02-23        kinaba: #include <queue>
4fd800b3a8 2011-02-23        kinaba: #include <stack>
4fd800b3a8 2011-02-23        kinaba: #include <cmath>
4fd800b3a8 2011-02-23        kinaba: #include <cassert>
4fd800b3a8 2011-02-23        kinaba: #include <cstring>
4fd800b3a8 2011-02-23        kinaba: using namespace std;
4fd800b3a8 2011-02-23        kinaba: typedef long long LL;
4fd800b3a8 2011-02-23        kinaba: typedef complex<double> CMP;
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba: class NextHomogeneousStrings { public:
4fd800b3a8 2011-02-23        kinaba: 	string getNext(int d, int n, string seed, long long k)
4fd800b3a8 2011-02-23        kinaba: 	{
4fd800b3a8 2011-02-23        kinaba: 		int M = seed.size();
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba: 		LL L=0, R=1; // [L,R)
4fd800b3a8 2011-02-23        kinaba: 		while( R-L > 2 ) {
4fd800b3a8 2011-02-23        kinaba: 			LL C = (R+L)/2;
4fd800b3a8 2011-02-23        kinaba: 			string t = xth(d,n,C,M);
4fd800b3a8 2011-02-23        kinaba: 			(t=="" || seed<t ? R : L) = C;
4fd800b3a8 2011-02-23        kinaba: 		}
4fd800b3a8 2011-02-23        kinaba: 		return seed==xth(d,n,L,M) ? xth(d,n,L+k-1,M) : xth(d,n,L+k,M);
4fd800b3a8 2011-02-23        kinaba: 	}
4fd800b3a8 2011-02-23        kinaba: 	string xth(int d, int n, LL x, int M)
4fd800b3a8 2011-02-23        kinaba: 	{
4fd800b3a8 2011-02-23        kinaba: 		return rec( string(), x, d, n, M );
4fd800b3a8 2011-02-23        kinaba: 	}
4fd800b3a8 2011-02-23        kinaba: 	string rec( string hist, LL x, int d, int n, int M )
4fd800b3a8 2011-02-23        kinaba: 	{
4fd800b3a8 2011-02-23        kinaba: 		if( M == 0 )
4fd800b3a8 2011-02-23        kinaba: 			return "";
4fd800b3a8 2011-02-23        kinaba: 		for(char c='a'; c<='z'; ++c)
4fd800b3a8 2011-02-23        kinaba: 		{
4fd800b3a8 2011-02-23        kinaba: 			string hh = hist + c;
4fd800b3a8 2011-02-23        kinaba: 			// todo: normalize
4fd800b3a8 2011-02-23        kinaba: 			if( x < cnt(hh,d,n,M) )
4fd800b3a8 2011-02-23        kinaba: 				return c + rec(hist+c, x, d, n, M-1);
4fd800b3a8 2011-02-23        kinaba: 			x -= cnt(hh,d,n,M);
4fd800b3a8 2011-02-23        kinaba: 		}
4fd800b3a8 2011-02-23        kinaba: 		return "";
4fd800b3a8 2011-02-23        kinaba: 	}
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba: 	LL cnt(string hist, int d, int n, int M)
4fd800b3a8 2011-02-23        kinaba: 	{
4fd800b3a8 2011-02-23        kinaba: 		if( M == 0 )
4fd800b3a8 2011-02-23        kinaba: 			return 1;
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba: 		// todo: memoize
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba: 		LL ans = 0;
4fd800b3a8 2011-02-23        kinaba: 		for(char c='a'; c<='z'; ++c)
4fd800b3a8 2011-02-23        kinaba: 		{
4fd800b3a8 2011-02-23        kinaba: 			char cc = c;
4fd800b3a8 2011-02-23        kinaba: 			if( find(hist.begin(), hist.end(), c)==hist.end() )
4fd800b3a8 2011-02-23        kinaba: 				cc = *max_element(hist.begin(),hist.end()) + 1; // todo: end then 'a'
4fd800b3a8 2011-02-23        kinaba: 			string h2 = hist+cc;
4fd800b3a8 2011-02-23        kinaba: 			// todo: check violation
4fd800b3a8 2011-02-23        kinaba: 			// todo: drop 1st (if needed)
4fd800b3a8 2011-02-23        kinaba: 			// todo: normalize
4fd800b3a8 2011-02-23        kinaba: 			//ans += cnt(h2, dd, nn, M-1);
4fd800b3a8 2011-02-23        kinaba: 		}
4fd800b3a8 2011-02-23        kinaba: 		return ans;
4fd800b3a8 2011-02-23        kinaba: 	}
4fd800b3a8 2011-02-23        kinaba: };
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba: // BEGIN CUT HERE
4fd800b3a8 2011-02-23        kinaba: #include <ctime>
4fd800b3a8 2011-02-23        kinaba: double start_time; string timer()
4fd800b3a8 2011-02-23        kinaba:  { ostringstream os; os << " (" << int((clock()-start_time)/CLOCKS_PER_SEC*1000) << " msec)"; return os.str(); }
4fd800b3a8 2011-02-23        kinaba: template<typename T> ostream& operator<<(ostream& os, const vector<T>& v)
4fd800b3a8 2011-02-23        kinaba:  { os << "{ ";
4fd800b3a8 2011-02-23        kinaba:    for(typename vector<T>::const_iterator it=v.begin(); it!=v.end(); ++it)
4fd800b3a8 2011-02-23        kinaba:    os << '\"' << *it << '\"' << (it+1==v.end() ? "" : ", "); os << " }"; return os; }
4fd800b3a8 2011-02-23        kinaba: void verify_case(const string& Expected, const string& Received) {
4fd800b3a8 2011-02-23        kinaba:  bool ok = (Expected == Received);
4fd800b3a8 2011-02-23        kinaba:  if(ok) cerr << "PASSED" << timer() << endl;  else { cerr << "FAILED" << timer() << endl;
4fd800b3a8 2011-02-23        kinaba:  cerr << "\to: \"" << Expected << '\"' << endl << "\tx: \"" << Received << '\"' << endl; } }
4fd800b3a8 2011-02-23        kinaba: #define CASE(N) {cerr << "Test Case #" << N << "..." << flush; start_time=clock();
4fd800b3a8 2011-02-23        kinaba: #define END	 verify_case(_, NextHomogeneousStrings().getNext(d, n, seed, k));}
4fd800b3a8 2011-02-23        kinaba: int main(){
4fd800b3a8 2011-02-23        kinaba: 
4fd800b3a8 2011-02-23        kinaba: CASE(0)
4fd800b3a8 2011-02-23        kinaba: 	int d = 1;
4fd800b3a8 2011-02-23        kinaba: 	int n = 2;
4fd800b3a8 2011-02-23        kinaba: 	string seed = "aaa";
4fd800b3a8 2011-02-23        kinaba: 	long long k = 3LL;
4fd800b3a8 2011-02-23        kinaba: 	string _ = "ddd";
4fd800b3a8 2011-02-23        kinaba: END
4fd800b3a8 2011-02-23        kinaba: CASE(1)
4fd800b3a8 2011-02-23        kinaba: 	int d = 2;
4fd800b3a8 2011-02-23        kinaba: 	int n = 3;
4fd800b3a8 2011-02-23        kinaba: 	string seed = "abc";
4fd800b3a8 2011-02-23        kinaba: 	long long k = 0LL;
4fd800b3a8 2011-02-23        kinaba: 	string _ = "aca";
4fd800b3a8 2011-02-23        kinaba: END
4fd800b3a8 2011-02-23        kinaba: CASE(2)
4fd800b3a8 2011-02-23        kinaba: 	int d = 2;
4fd800b3a8 2011-02-23        kinaba: 	int n = 4;
4fd800b3a8 2011-02-23        kinaba: 	string seed = "ttrrzz";
4fd800b3a8 2011-02-23        kinaba: 	long long k = 6LL;
4fd800b3a8 2011-02-23        kinaba: 	string _ = "ttsssc";
4fd800b3a8 2011-02-23        kinaba: END
4fd800b3a8 2011-02-23        kinaba: CASE(3)
4fd800b3a8 2011-02-23        kinaba: 	int d = 6;
4fd800b3a8 2011-02-23        kinaba: 	int n = 8;
4fd800b3a8 2011-02-23        kinaba: 	string seed = "txyaaxaassaaaarghjsdohasdghususdidisisdodo";
4fd800b3a8 2011-02-23        kinaba: 	long long k = 10000000000000000LL;
4fd800b3a8 2011-02-23        kinaba: 	string _ = "txyaaxaassaaaarghjsgaaaaaaaaadntffiniqrddy";
4fd800b3a8 2011-02-23        kinaba: END
4fd800b3a8 2011-02-23        kinaba: CASE(4)
4fd800b3a8 2011-02-23        kinaba: 	int d = 2;
4fd800b3a8 2011-02-23        kinaba: 	int n = 5;
4fd800b3a8 2011-02-23        kinaba: 	string seed = "zzzzzaa";
4fd800b3a8 2011-02-23        kinaba: 	long long k = 100LL;
4fd800b3a8 2011-02-23        kinaba: 	string _ = "";
4fd800b3a8 2011-02-23        kinaba: END
4fd800b3a8 2011-02-23        kinaba: /*
4fd800b3a8 2011-02-23        kinaba: CASE(5)
4fd800b3a8 2011-02-23        kinaba: 	int d = ;
4fd800b3a8 2011-02-23        kinaba: 	int n = ;
4fd800b3a8 2011-02-23        kinaba: 	string seed = ;
4fd800b3a8 2011-02-23        kinaba: 	long long k = LL;
4fd800b3a8 2011-02-23        kinaba: 	string _ = ;
4fd800b3a8 2011-02-23        kinaba: END
4fd800b3a8 2011-02-23        kinaba: CASE(6)
4fd800b3a8 2011-02-23        kinaba: 	int d = ;
4fd800b3a8 2011-02-23        kinaba: 	int n = ;
4fd800b3a8 2011-02-23        kinaba: 	string seed = ;
4fd800b3a8 2011-02-23        kinaba: 	long long k = LL;
4fd800b3a8 2011-02-23        kinaba: 	string _ = ;
4fd800b3a8 2011-02-23        kinaba: END
4fd800b3a8 2011-02-23        kinaba: */
4fd800b3a8 2011-02-23        kinaba: }
4fd800b3a8 2011-02-23        kinaba: // END CUT HERE