| # | Submission time | Handle | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 869851 | 2023-11-06T01:56:33 Z | Lib | Rarest Insects (IOI22_insects) | C++17 | 0 ms | 0 KB |
#include <bits/stdc++.h>
#include "insects.h"
//#include "stub.cpp"
using namespace std;
deque <int> PrevIndex;
int InMachine[2003];
int n;
int TypeCount=0;
int CurrentInMachine=0;
int min_cardinality(int N){
int l,r,mid;
n=N;
l=1;
//Phase 1: Determining the amount of different types of insects
for(int i=0;i<n;i++){
move_inside(i);
InMachine[i]=1;
PrevIndex.push_back(i);
if(press_button()>1){
move_outside(i);
InMachine[i]=0;
PrevIndex.pop_back();
}
}
TypeCount=PrevIndex.size();
r=(n/TypeCount);
const auto PossibleMincount=[&](int cnt){
PrevIndex.clear();
//Pushing insects inside the machine, keeping track of the ones being putted inside for this iteration of binary searching
for(int i=0;i<n;i++){
if(!InMachine[i]){
InMachine[i]=1;
move_inside(i);
PrevIndex.push_back(i);
if(press_button()>cnt){
move_outside(i);
InMachine[i]=0;
PrevIndex.pop_back();
}
}
}
CurrentInMachine=0;
for(int i=0;i<n;i++){
CurrentInMachine+=InMachine[i];
}
if(CurrentInMachine<cnt*TypeCount){
//There clearly exist a type of insect with cardinality less than cnt, so the answer is less than cnt. Removing insects from last iteration.
while(!PrevIndex.empty()){
InMachine[PrevIndex.front()]=0;
move_outside(PrevIndex.front());
PrevIndex.pop_front();
}
return false;
}else if(CurrentInMachine==cnt*TypeCount){
//As every type of insects has at least cnt insects, the answer is at least cnt. Just return true
PrevIndex.clear();
return true;
}
}
//Phase 2: Binary search for the answer
//return press_button();
while(r-l>=1){
mid=(l+r)/2;
if(PossibleMincount(mid)){
l=mid;
}else{
r=mid-1;
}
}
if(PossibleMincount(l)){
return l;
}else{
return r;
}
}