Submission #1076516

#	Time	Username	Problem	Language	Result	Execution time	Memory
1076516		mindiyak	Counting Mushrooms (IOI20_mushrooms)	C++14	62.26 / 100	7 ms	780 KiB

mushrooms

#include "mushrooms.h"
#include <iostream>
#include <vector>
#include <algorithm>
#include <deque>

using namespace std;

const int S = 210;

int brute(int n){
	//A = 0 | B = 1
	vector<int> type(n,-1);
	type[0] = 0;
 
	int pos = -1;
	for(int i = 1;i<n;i++){
		if(use_machine({0,i}) == 0){
			pos = i;
			type[i] = 0;
			break;
		}else{
			type[i] = 1;
		}
	}
 
	// cerr << pos << endl;
	int a=pos+1,b=pos+2;
 
	while(pos != -1){
		if(a >= n)break; 
		if(b >= n){
			if(use_machine({0,a}) == 0){
				type[a] = 0;
			}else{
				type[a] = 1;
			}
		}else{
			int val = use_machine({a,0,b,pos});
			if(val == 0){
				type[a] = 0;
				type[b] = 0;
			}else if(val == 1){
				type[a] = 1;
				type[b] = 0;
			}else if(val == 2){
				type[a] = 0;
				type[b] = 1;
			}else if(val == 3){
				type[a] = 1;
				type[b] = 1;
			}
		}
		a += 2;
		b += 2;
	}
 
	int ans = 0;
	// for(int i=0;i<n;i++)cerr << type[i] << " ";
	// cerr << endl;
	for(int i=0;i<n;i++)ans += (type[i]+1)%2;
	return ans;
}

int count_mushrooms(int n) {

	if(n < S+20)return brute(n);

	vector<int> A,B;
	deque<int> left;
	A.push_back(0);

	for(int i=1;i<n;i++)left.push_back(i);

	while(max(A.size(),B.size()) < S && left.size() > 0){
		int val = use_machine({0,left[0],left[1]});
		if(val == 0){
			A.push_back(left[0]);
			A.push_back(left[1]);
		}else if(val == 1){
			B.push_back(left[1]);
			left.push_back(left[0]);
		}else{
			B.push_back(left[0]);
			A.push_back(left[1]);
		}
		left.pop_front();
		left.pop_front();
	}

	int ans = A.size();

	while(left.size() > 0){
		if(A.size() > B.size()){
			vector<int> q;
			int m = 0,k = 0;
			while(m < A.size() && k < left.size()){
				q.push_back(left[k]);k++;
				q.push_back(A[m]);m++;
			}
			int val = use_machine(q);
			ans += k-(val+1)/2;
			if(val%2 == 1)B.push_back(left[0]);
			else A.push_back(left[0]);
			for(int i = 0;i<k;i++)left.pop_front();
		}else{
			vector<int> q;
			int m = 0,k = 0;
			while(m < B.size() && k < left.size()){
				q.push_back(left[k]);k++;
				q.push_back(B[m]);m++;
			}
			int val = use_machine(q);
			ans += (val+1)/2;
			if(val%2 == 1)A.push_back(left[0]);
			else B.push_back(left[0]);
			for(int i = 0;i<k;i++)left.pop_front();
		}
	}

	return ans;
}

Compilation message (stderr)

mushrooms.cpp: In function 'int count_mushrooms(int)':
mushrooms.cpp:97:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   97 |    while(m < A.size() && k < left.size()){
      |          ~~^~~~~~~~~~
mushrooms.cpp:97:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::deque<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   97 |    while(m < A.size() && k < left.size()){
      |                          ~~^~~~~~~~~~~~~
mushrooms.cpp:109:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  109 |    while(m < B.size() && k < left.size()){
      |          ~~^~~~~~~~~~
mushrooms.cpp:109:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::deque<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  109 |    while(m < B.size() && k < left.size()){
      |                          ~~^~~~~~~~~~~~~

• Subtask 1: 62.259 / 100