// includes {{{ #include #include #include #include #include #include #include #include #include #include #include #include #include #include // #include // #include // #include // #include // }}} using namespace std; using ll = long long; // #undef DEBUG // #define DEBUG // DEBUG {{{ #include #include #include #include #include #include #include #include #include template < int n, class... T > typename std::enable_if< (n >= sizeof...(T)) >::type __output_tuple( std::ostream &, std::tuple< T... > const &) {} template < int n, class... T > typename std::enable_if< (n < sizeof...(T)) >::type __output_tuple( std::ostream &os, std::tuple< T... > const &t) { os << (n == 0 ? "" : ", ") << std::get< n >(t); __output_tuple< n + 1 >(os, t); } template < class... T > std::ostream &operator<<(std::ostream &os, std::tuple< T... > const &t) { os << "("; __output_tuple< 0 >(os, t); os << ")"; return os; } template < class T, class U > std::ostream &operator<<(std::ostream &os, std::pair< T, U > const &p) { os << "(" << p.first << ", " << p.second << ")"; return os; } template < class T > std::ostream &operator<<(std::ostream &os, const std::stack< T > &a) { os << "{"; for(auto tmp = a; tmp.size(); tmp.pop()) os << (a.size() == tmp.size() ? "" : ", ") << tmp.top(); os << "}"; return os; } template < class T, class Container, class Compare > std::ostream &operator<<(std::ostream &os, std::priority_queue< T, Container, Compare > a) { os << "{ (top) "; while(a.size()) os << a.top() << (a.size() == 1 ? "" : ", "), a.pop(); os << " }"; return os; } template < class T, class Container > std::ostream &operator<<(std::ostream &os, std::queue< T, Container > a) { os << "{ "; while(a.size()) os << a.front() << (a.size() == 1 ? "" : ", "), a.pop(); os << " }"; return os; } #ifdef DEBUG #if !defined(DEBUG_OUT) #define DEBUG_OUT std::cerr #endif #define dump(...) \ [&]() { \ auto __debug_tap = std::make_tuple(__VA_ARGS__); \ DEBUG_OUT << "[" << __LINE__ << "] " << #__VA_ARGS__ << " = " << __debug_tap \ << std::endl; \ }() template < class T > inline void dump2D(T &d, size_t sizey, size_t sizex) { for(size_t i = 0; i < sizey; i++) { DEBUG_OUT << "\t"; for(size_t j = 0; j < sizex; j++) DEBUG_OUT << d[i][j] << (j + 1 == sizex ? "" : "\t"); DEBUG_OUT << std::endl; } } template < class T > inline void dump1D(T &d, size_t sizey) { for(size_t i = 0; i < sizey; i++) { DEBUG_OUT << d[i] << (i + 1 == sizey ? "" : " "); } DEBUG_OUT << std::endl; } template < class T, class = typename std::iterator_traits< decltype(begin(T())) >::value_type, class = typename std::enable_if< !std::is_same< T, std::string >::value >::type > std::ostream &operator<<(std::ostream &os, const T &a) { os << "{"; for(auto ite = begin(a); ite != end(a); ++ite) os << (ite == begin(a) ? "" : ", ") << *ite; os << "}"; return os; } #else #define dump(...) ((void) 42) #define dump2D(...) ((void) 42) #define dump1D(...) ((void) 42) template < class T, class = typename std::iterator_traits< decltype(begin(T())) >::value_type, class = typename std::enable_if< !std::is_same< T, std::string >::value >::type > std::ostream &operator<<(std::ostream &os, const T &a) { for(auto ite = begin(a); ite != end(a); ++ite) os << (ite == begin(a) ? "" : " ") << *ite; return os; } #endif // }}} int n; // 二番目に小さい vector v; // is x < y bool ask(int x, int y) { #ifdef DEBUG static bool f = 0; if(!f){ v.resize(n + 1); f = 1; iota(begin(v) + 1, end(v), 1); static random_device rnd; static mt19937 mt(rnd()); shuffle(begin(v) + 1, end(v), mt); dump(v); } return v[x] < v[y]; #endif static int num = 0; num++; if(num > 334) assert(0); cout << "? " << x << " " << y << endl; int s; cin >> s; if(s == x) return true; else return false; } void ans(int x) { #ifdef DEBUG dump(v[x]); #endif cout << "! " << x << endl; exit(0); } int main() { // int n = 300; // for(int m = 2; m <= 50; m++) { // int x = n - 1 + m - 1 + ceil(log2((n + m - 1) / m)) - 1; // dump(m, x); // } cin >> n; vector v(n + 1); iota(v.begin(), v.end(), 0); vector pars; vector*> secs; for(int i = 1; i <= n; i += 2) { if(i+1 <= n) { if(!ask(v[i], v[i+1])) swap(v[i], v[i+1]); // v[i] < v[i+1] pars.push_back(v[i]); vector* vp = new vector({v[i+1]}); secs.push_back(vp); } else { pars.push_back(v[i]); secs.push_back(new vector); } } while(pars.size() >= 2) { assert(pars.size() == secs.size()); int k = pars.size(); vector newpars; vector*> newsecs; for(int i = 0; i < k; i+=2) { if(i+1 < k) { if(!ask(pars[i], pars[i+1])) swap(pars[i], pars[i+1]), swap(secs[i], secs[i+1]); // pars[i] < pars[i+1] newpars.push_back(pars[i]); newsecs.push_back(secs[i]); newsecs.back()->push_back(pars[i+1]); } else { newpars.push_back(pars[i]); newsecs.push_back(secs[i]); } } pars = newpars; secs = newsecs; } int mini = n + 1; for(auto e : *secs.back()) { if(mini == n + 1) mini = e; else mini = ask(mini, e) ? mini : e; } ans(mini); return 0; }