Submission #641244

#	Time	Username	Problem	Language	Result	Execution time	Memory
641244		TimDee	Rarest Insects (IOI22_insects)	C++17	99.89 / 100	69 ms	316 KiB

insects

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

int n,d;
vector<int> in(2005,0);
vector<int> uniq;

int f(int l, int r, vector<int> from) {
  if (r-l==0) {
    move_outside(uniq[r]);
    return from.size()+1;
  }
  int mid=(l+r+1)>>1;
  vector<int> left, right;
  for (int i=mid; i<=r; ++i) move_outside(uniq[i]);
  for (auto x:from) {
    move_inside(x);
    int k=press_button();
    if (k>1) left.push_back(x);
    else right.push_back(x);
    move_outside(x);
  }
  int L=f(l,mid-1,left);
  //for (int i=0; i<mid; ++i) move_outside(uniq[i]);
  for (int i=mid; i<=r; ++i) move_inside(uniq[i]);
  int R=f(mid,r,right);
  return min(L,R);
}

int min_cardinality(int N) {
  n=N;
  d=0;
  for(int i=0; i<n; ++i) {
    move_inside(i);
    int x=press_button();
    if (x>1) move_outside(i);
    else { in[i]=1; ++d; }
  }

  for (int i=0; i<n; ++i) if (in[i]) uniq.push_back(i);
  if (d==1) return n;
  if (d>n/2) return 1;
  if (d<=2) {
    int ans=n;
    vector<int> vis(n,0);
    for (int i=0; i<n; ++i) vis[i]=in[i];
    for (int i=0; i<d; ++i) {
      vector<int> bulaneala;
      int cnt=1;
      for (int i=0; i<n; ++i) {
        if (vis[i]) continue;
        move_inside(i);
        int x=press_button();
        if (x==cnt) move_outside(i);
        else {
          bulaneala.push_back(i);
          ++cnt;
          vis[i]=1;
        }
      }
      ans=min(ans,cnt);
      for (auto x:bulaneala) move_outside(x);
    }
    return ans;
  }

  if (d<=n) {
    int l=0, r=d-1;
    vector<int> scuza;
    for (int i=0; i<n; ++i) if (!in[i]) scuza.push_back(i);
    //return f(l,r,scuza);
  }

  int l=1, r=n/d;
  int now=d;
  vector<int> use; 
  for (int i=0; i<n; ++i) {
    if (in[i]) continue;
    use.push_back(i);
  }
  while (l<r) {
    vector<int> add;
    int mid=(l+r+1)>>1;
    int extra=0;
    int cnt=now;
    for (auto x:use) {
      if (in[x]) continue;
      in[x]=1;
      move_inside(x);
      int X=press_button();
      if (X>mid) {
        extra=1;
        move_outside(x);
        in[x]=0;
      } else {
        ++cnt;
        add.push_back(x);
      }
    }
    if (cnt==mid*d) {
      if (extra==0) {
        return mid;
      } else {
        l=mid;
        now=cnt;
      }
    } else {
      now=cnt;
      r=mid-1;
      use=add;
      for (auto x:add) {
        --now;
        in[x]=0;
        move_outside(x);
      }
    }
  }
  return r;

}

Compilation message (stderr)

insects.cpp: In function 'int min_cardinality(int)':
insects.cpp:69:9: warning: unused variable 'l' [-Wunused-variable]
   69 |     int l=0, r=d-1;
      |         ^
insects.cpp:69:14: warning: unused variable 'r' [-Wunused-variable]
   69 |     int l=0, r=d-1;
      |              ^

• Subtask 1: 10 / 10
• Subtask 2: 15 / 15
• Subtask 3: 74.89 / 75