Submission #799805

#	Time	Username	Problem	Language	Result	Execution time	Memory
799805		QwertyPi	Counting Mushrooms (IOI20_mushrooms)	C++14	80.71 / 100	7 ms	440 KiB

mushrooms

#include "mushrooms.h"

std::vector<int> a[2];
int b[2];

int id, n;
void query_1(){
	if(id >= n) return;
	std::vector<int> m {0, id};
	int c = use_machine(m);
	a[c].push_back(id);
	id++;
}

void query_2(){
	if(id >= n) return;
	if(a[0].size() <= 1 && a[1].size() <= 1 || id == n - 1){ query_1(); return; }
	int majority = a[0].size() >= a[1].size() ? 0 : 1;
	std::vector<int> m = {a[majority][0], id, a[majority][1], id + 1};
	int c = use_machine(m);
	id += 2;
	a[majority ^ (c / 2)].push_back(m[1]);
	a[majority ^ (c % 2)].push_back(m[3]);
}

void query_3(){
	if(id >= n) return;
	if(a[0].size() <= 1 && a[1].size() <= 1){ query_1(); return; }
	int majority = a[0].size() >= a[1].size() ? 0 : 1;
	int k = a[majority].size(); k = std::min(k, n - id);
	std::vector<int> m;
	for(int i = id; i < id + k; i++){
		m.push_back(a[majority][i - id]); m.push_back(i);
	}
	int c = use_machine(m);
	id += k;
	a[majority ^ (c % 2)].push_back(m.back());
	b[majority ^ 1] += c / 2;
	b[majority] += (k - 1) - c / 2;
}

int count_mushrooms(int N) {
	n = N; a[0].push_back(0); id = 1;
	if(n <= 1000){
		while(id < n) query_3();
		return a[0].size() + b[0];
	}
	while(id < n) query_3();
	return a[0].size() + b[0];
}

Compilation message (stderr)

mushrooms.cpp: In function 'void query_2()':
mushrooms.cpp:17:22: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   17 |  if(a[0].size() <= 1 && a[1].size() <= 1 || id == n - 1){ query_1(); return; }
      |     ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~

• Subtask 1: 80.7143 / 100