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Submission #305167

# Submission time Handle Problem Language Result Execution time Memory
305167 2020-09-22T16:45:44 Z aljasdlas Counting Mushrooms (IOI20_mushrooms) C++14
0 / 100
 2 ms 256 KB 
#include "mushrooms.h"
#include <bits/stdc++.h>
using namespace std;

int count_mushrooms(int n) {
	if(n < 220) {
		int B = 0;
		for(int i = 1; i < n; i++) {
			B += use_machine({0, i});
		}
		return n-B;
	}

	vector<int> perm;
	for(int i = 1; i < n; i++)
		perm.push_back(i);
	
	srand(time(0));

	vector<int> A, B;
	A = {0};
	if(use_machine({0,1})) B.push_back(1);
	else A.push_back(1);
	if(use_machine({0,2})) B.push_back(2);
	else A.push_back(2);

	if(B.size() > A.size()) swap(A,B);

	for(int i = 3; i < n && (A.size()-1)*(A.size()-1) < (n-A.size()-B.size()) && (B.size()-1)*(B.size()-1) < (n-A.size()-B.size()); i+=2) {
		vector<int> cur;
		cur.push_back(A[0]);
		cur.push_back(i);
		cur.push_back(A[1]);
		if(i+1 < n) cur.push_back(i+1);

		// for(auto x: cur) cerr << x << " ";
		// cerr << endl;
		int res = use_machine(cur);

		if(res & 2) B.push_back(i);
		else A.push_back(i);

		if(i+1 < n) {
			if(res & 1) B.push_back(i+1);
			else A.push_back(i+1);
		}
	}

	if(B.size() > A.size()) swap(A,B);

	int countA = 0;
	int countB = 0;
	for(int i = A.size()+B.size(); i < n; i+=A.size()) {
		vector<int> cur;
		int j = 0;
		for(j = 0; i+j < n && j < A.size(); j++) {
			cur.push_back(A[j]);
			cur.push_back(i+j);
		}

		// for(auto x: cur) cerr << x << " ";
		// cerr << ": ";
		int res = use_machine(cur);
		countB += (res+1)/2;
		countA += j - ((res+1)/2);

		if(res % 2 == 0) {
			B.push_back(cur.back());
		} else {
			A.push_back(cur.back());
		}

		if(B.size() > A.size()) swap(A,B);
		// cerr << res << " -> " << countA << " " << countA << endl;;
	}

	if(A[0] == 0) return A.size()+countA;
	else return B.size()+countB;
}

Compilation message

mushrooms.cpp: In function 'int count_mushrooms(int)':
mushrooms.cpp:56:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |   for(j = 0; i+j < n && j < A.size(); j++) {
      |                         ~~^~~~~~~~~~

Subtask #1
0 / 100.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 256 KB Output is correct
2 Correct 0 ms 256 KB Output is correct
3 Correct 0 ms 256 KB Output is correct
4 Correct 1 ms 256 KB Output is correct
5 Correct 2 ms 256 KB Output is correct
6 Incorrect 2 ms 256 KB Answer is not correct.
7 Halted 0 ms 0 KB -