Artifact efb89f3f41758ae4010eb7decf5e3964bb438237
#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 <tuple>
using namespace std;
typedef long long LL;
typedef complex<double> CMP;
class HappyLetterDiv1 { public:
string getHappyLetters(string letters)
{
set<char> cs(letters.begin(), letters.end());
string ans;
for(char c: cs)
if(can_win(c, letters))
ans += c;
return ans;
}
bool can_win(char c, const string& s)
{
string rest;
string cs;
for(char ch: s) (ch==c ? cs : rest) += ch;
if(rest.size()%2==1) {
rest += c;
cs.resize(cs.size()-1);
}
while(!cs.empty()) {
if(can_erase(rest))
return true;
if(cs.size()<2)
break;
rest += string(2, c);
cs.resize(cs.size()-2);
}
return false;
}
bool can_erase(string s)
{
map<char, int> cnt;
int maxCnt = 0;
for(char c: s) maxCnt = max(maxCnt, ++cnt[c]);
return maxCnt*2 <= s.size();
}
};
// 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 string& Expected, const string& 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(_, HappyLetterDiv1().getHappyLetters(letters));}
int main(){
CASE(0)
string letters = "aabbacccc";
string _ = "abc";
END
CASE(1)
string letters = "aaaaaaaccdd";
string _ = "a";
END
CASE(2)
string letters = "ddabccadb";
string _ = "abcd";
END
CASE(3)
string letters = "aaabbb";
string _ = "";
END
CASE(4)
string letters = "rdokcogscosn";
string _ = "cos";
END
/*
CASE(5)
string letters = ;
string _ = ;
END
CASE(6)
string letters = ;
string _ = ;
END
*/
}
// END CUT HERE