Submission #600559

#	Time	Username	Problem	Language	Result	Execution time	Memory
600559		kig9981	Counting Mushrooms (IOI20_mushrooms)	C++17	91.50 / 100	11 ms	520 KiB

mushrooms

#include "mushrooms.h"
#include <bits/stdc++.h>

#ifdef NON_SUBMIT
#define TEST(n) (n)
#define tout cerr
#else
#define TEST(n) ((void)0)
#define tout cin
#endif

using namespace std;

vector<int> A, B, Q;
int D[3];

void query1()
{
	int a=Q.back(), b, r; Q.pop_back();
	b=Q.back(); Q.pop_back();
	if(A.size()>1) {
		r=use_machine({A[0],a,A[1],b});
		if(r&1) B.push_back(b);
		else A.push_back(b);
		if(r>1) B.push_back(a);
		else A.push_back(a);
	}
	else {
		r=use_machine({B[0],a,B[1],b});
		if(r&1) A.push_back(b);
		else B.push_back(b);
		if(r>1) A.push_back(a);
		else B.push_back(a);
	}
}

int query2()
{
	int m=min(Q.size(),max(A.size(),B.size())), r;
	vector<int> I;
	if(A.size()>=m) {
		for(int i=0;i<m;i++) {
			I.push_back(A[i]); I.push_back(Q.back());
			Q.pop_back();
		}
		r=use_machine(I);
		if(r&1) B.push_back(I.back());
		else A.push_back(I.back());
		return m-1-(r>>1);
	}
	else {
		for(int i=0;i<m;i++) {
			I.push_back(B[i]); I.push_back(Q.back());
			Q.pop_back();
		}
		r=use_machine(I);
		if(r&1) A.push_back(I.back());
		else B.push_back(I.back());
		return r>>1;
	}
}

int count_mushrooms(int n)
{
	int ret=0;
	mt19937 mt(chrono::high_resolution_clock::now().time_since_epoch().count());
	if(n-1<=226) {
		ret=1;
		for(int i=1;i<n;i++) ret+=!use_machine({0,i});
		return ret;
	}
	for(int i=1;i<n;i++) Q.push_back(i);
	shuffle(Q.begin(),Q.end(),mt);
	A.push_back(0);
	while(max(A.size(),B.size())<2 || (Q.size()&1)) {
		int c=Q.back();
		Q.pop_back();
		if(use_machine({0,c})) B.push_back(c);
		else A.push_back(c);
	}
	for(int i=0;i<101;i++) {
		if(Q.empty()) break;
		query1();
	}
	while(Q.size()) ret+=query2();
	return ret+A.size();
}

Compilation message (stderr)

mushrooms.cpp: In function 'int query2()':
mushrooms.cpp:41:13: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   41 |  if(A.size()>=m) {
      |     ~~~~~~~~^~~

• Subtask 1: 91.498 / 100