#include <bits/extc++.h>
using namespace std;
using namespace __gnu_pbds;
#define int long long
typedef int64_t ll;
typedef long double ld;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define pb emplace_back
#define mp make_pair
#define mt make_tuple
#define pii pair<int,int>
#define F(n) Fi(i,n)
#define Fi(i,n) Fl(i,0,n)
#define Fl(i,l,n) for(int i=l;i<n;i++)
#define RF(n) RFi(i,n)
#define RFi(i,n) RFl(i,0,n)
#define RFl(i,l,n) for(int i=n-1;i>=l;i--)
#define all(v) begin(v),end(v)
#define siz(v) (ll(v.size()))
#define get_pos(v,x) (lower_bound(all(v),x)-begin(v))
#define sort_uni(v) sort(begin(v),end(v)),v.erase(unique(begin(v),end(v)),end(v))
#define mem(v,x) memset(v,x,sizeof v)
#define ff first
#define ss second
#define mid ((l+r)>>1)
#define RAN(a,b) uniform_int_distribution<int> (a, b)(rng)
#define debug(x) (cerr << (#x) << " = " << x << "\n")
#define cmax(a,b) (a = max(a,b))
#define cmin(a,b) (a = min(a,b))
template <typename T> using max_heap = __gnu_pbds::priority_queue<T,less<T> >;
template <typename T> using min_heap = __gnu_pbds::priority_queue<T,greater<T> >;
template <typename T> using rbt = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;
//int C;
int pre = 0;
set<int> used;
int q(int c){
printf("? %lld\n", c);
cout.flush();
used.insert(c);
/*
bool b = (abs(pre - c) >= C);
pre = c;
return b;
*/
int x;
cin >> x;
return x;
}
signed main(){
int N;
cin >> N;
int l = 0, r = N;
int dis = 0;
int flip = 0;
while(l+1 != r){
if(flip) dis -= mid;
else dis += mid;
l = mid;
flip = 1 - flip;
}
if(dis < 0) dis = -dis;
debug(dis);
int pointer = dis+1;
q(pointer);
l = 0, r = N;
while(l+1 != r){
if(pointer + mid <= N && !s.count(pointer+mid)){
pointer += mid;
}else if(pointer-mid >= 1 && !s.count(pointer-mid)){
pointer -= mid;
}else{
q(1);
pointer = 1;
continue;
}
if(q(pointer)){
r = mid;
}else{
l = mid;
}
}
printf("= %lld\n", r);
return 0;
}
Compilation message
Colors.cpp: In function 'int main()':
Colors.cpp:82:31: error: 's' was not declared in this scope
82 | if(pointer + mid <= N && !s.count(pointer+mid)){
| ^
