#include using namespace std; int main(){ int l = 1,r = 1000001; int prevx = 0,nowx = -1; cout << "? 0" << endl; while(abs(l-r) > 1){ int mid = (l + r) / 2; nowx = mid + (mid-prevx); cout << "? " << nowx << endl; int get; cin >> get; if(nowx >= prevx){ if(bool(get))l = mid; else r = mid; } else { if(bool(get))r = mid+1; else l = mid+1; } prevx = nowx; } cout << "! " << l << endl; return 0; }