Submission #628152

#	Time	Username	Problem	Language	Result	Execution time	Memory
628152		haojiandan	Rarest Insects (IOI22_insects)	C++17	100 / 100	62 ms	428 KiB

insects

#include "insects.h"
#include <bits/stdc++.h>
using namespace std;
int n;
int p[10000];
int min_cardinality(int _n) {
	n=_n; vector<int> V; int cnt=0;
	for (int i=0;i<n;i++) p[i]=i; random_shuffle(p,p+n);
	for (int i=0;i<n;i++) {
		move_inside(p[i]);
		if (press_button()>1) move_outside(p[i]),V.push_back(p[i]); else cnt++;
	}
	if (cnt==1) return n;
	if (cnt==2) {
		for (int i=0;i<n;i++) move_inside(i);
		return n-press_button();
	}
	int l=2,r=n/cnt,mid,res=1;
	int lst=1;
	while (l<=r) {
		mid=(l+r)>>1;
		vector<int> V1,V2; int c=0;
		int id=0;
		for (int &x : V) {
			move_inside(x); id++;
			if (press_button()>mid) move_outside(x),V2.push_back(x); else c++,V1.push_back(x);
			if (c==cnt*(mid-lst)) { for (int i=id;i<V.size();i++) V2.push_back(V[i]); break; }
		}
		if (c==cnt*(mid-lst)) {
			res=mid; V.swap(V2); lst=mid; l=mid+1;
		} else {
			r=mid-1; for (int &x : V1) move_outside(x); V.swap(V1);
		}
	}
	return res;
}

Compilation message (stderr)

insects.cpp: In function 'int min_cardinality(int)':
insects.cpp:8:2: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
    8 |  for (int i=0;i<n;i++) p[i]=i; random_shuffle(p,p+n);
      |  ^~~
insects.cpp:8:32: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
    8 |  for (int i=0;i<n;i++) p[i]=i; random_shuffle(p,p+n);
      |                                ^~~~~~~~~~~~~~
insects.cpp:27:43: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |    if (c==cnt*(mid-lst)) { for (int i=id;i<V.size();i++) V2.push_back(V[i]); break; }
      |                                          ~^~~~~~~~~

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