Submission #1278505

#	Time	Username	Problem	Language	Result	Execution time	Memory
1278505		rtri	Colors (BOI20_colors)	C++20	0 / 100	1 ms	332 KiB

Colors

#include <bits/stdc++.h>
using namespace std;

typedef long long int ll;

bool ask(ll p) {
  cout << "? " << p << endl;
  bool ans;
  cin >> ans;
  return ans;
}

int main() {
  ll n;
  cin >> n;

  ll l = 0, r = n + 1;
  ll prev = 1;
  ask(1);
  while (1 < r - l) {
    ll mid = (l + r) / 2;
    ll next = prev + mid;
    if (0 < prev - mid)
      next = prev - mid;
    else if (n < next) {
      if (prev == 1) {
        r = n;
        break;
      }

      prev = 1;
      ask(prev);
      continue;
    }

    if (ask(next))
      r = mid;
    else
      l = mid;

    prev = next;
  }

  cout << "= " << r << endl;

  return 0;
}

• Subtask 1: 0 / 9
• Subtask 2: 0 / 13
• Subtask 3: 0 / 21
• Subtask 4: 0 / 24
• Subtask 5: 0 / 33