Submission #516427

#	Time	Username	Problem	Language	Result	Execution time	Memory
516427		Wayne_Yan	Colors (BOI20_colors)	C++17	100 / 100	2 ms	328 KiB

Colors

#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 && !used.count(pointer+mid)){
      pointer += mid;
    }else if(pointer-mid >= 1 && !used.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;
}

• Subtask 1: 9 / 9
• Subtask 2: 13 / 13
• Subtask 3: 21 / 21
• Subtask 4: 24 / 24
• Subtask 5: 33 / 33