Submission #834826

#	Time	Username	Problem	Language	Result	Execution time	Memory
834826		esomer	Rarest Insects (IOI22_insects)	C++17	0 / 100	327 ms	328 KiB

insects

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

using namespace std;

int groups, lft;
vector<bool> done;

int get_groups(int N){
	int groups = 0;
	for(int i = 0; i < N; i++){
		move_inside(i);
		int rep = press_button();
		if(rep > 1) { move_outside(i); }
		else { groups++; done[i] = 1; }
	}
	return groups;
}

int choose_best(int lo, int hi){
	//If I choose mid. Then in the case that all the groups are of size at least mid,
	//I discard (mid - lo + 1) * groups.
	//In the other case, I discard left - chosen (and chosen can be at most (mid - lo + 1) * groups).
	//So I want min((mid - lo + 1) * groups, left - (mid - lo + 1) * groups) to be the maximum.
	int x = lft / 2;
	int bst = x / groups;
	int mn1 = min(bst * groups, lft - bst * groups);
	bst++;
	int mn2 = min(bst * groups, lft - bst * groups);
	if(mn1 < mn2) bst--;
	return min(hi, lo + bst - 1);
}

int min_cardinality(int N) {
	done.assign(N, 0);
	int lo = 2;
	int hi = N;
	int ans = 1;
	groups = get_groups(N);
	lft = N - groups;
	int cnt = groups;
	while(lo <= hi) {
		int mid = choose_best(lo, hi);
		vector<int> good, bad;
		for(int i = 0; i < N; i++) {
			if(done[i]) { continue; }
			move_inside(i);
			int rep = press_button();
			if(rep > mid) {
				bad.push_back(i);
				move_outside(i);
			} else { good.push_back(i); }
		}
		if((int)good.size() + cnt == mid * groups) {
			ans = mid;
			lo = mid + 1;
			for(int x : good) done[x] = 1;
			cnt += (int)good.size();
			lft -= (int)good.size();
		} else {
			hi = mid - 1;
			for(int x : good) move_outside(x);
			for(int x : bad) done[x] = 1;
			lft -= (int)bad.size();
		}
	}
	return ans;
}

// static constexpr int kMaxQueries = 40000;

// static int N;
// // Insect types are compressed to colors in the range [0, N).
// static std::vector<int> color;
// static std::vector<bool> in_box;

// static std::vector<int> color_occurrences;
// static std::multiset<int> max_occurrences;

// static std::vector<int> op_counter(3, 0);

// static void protocol_violation(std::string message) {
//   printf("Protocol Violation: %s\n", message.c_str());
//   exit(0);
// }

// void move_inside(int i) {
//   if (i < 0 || i >= N) {
//     protocol_violation("invalid parameter");
//   }
//   ++op_counter[0];
//   if (op_counter[0] > kMaxQueries) {
//     protocol_violation("too many calls");
//   }
//   if (!in_box[i]) {
//     in_box[i] = true;
//     max_occurrences.erase(max_occurrences.find(color_occurrences[color[i]]));
//     ++color_occurrences[color[i]];
//     max_occurrences.insert(color_occurrences[color[i]]);
//   }
// }

// void move_outside(int i) {
//   if (i < 0 || i >= N) {
//     protocol_violation("invalid parameter");
//   }
//   ++op_counter[1];
//   if (op_counter[1] > kMaxQueries) {
//     protocol_violation("too many calls");
//   }
//   if (in_box[i]) {
//     in_box[i] = false;
//     max_occurrences.erase(max_occurrences.find(color_occurrences[color[i]]));
//     --color_occurrences[color[i]];
//     max_occurrences.insert(color_occurrences[color[i]]);
//   }
// }

// int press_button() {
//   ++op_counter[2];
//   if (op_counter[2] > kMaxQueries) {
//     protocol_violation("too many calls");
//   }
//   return *(max_occurrences.rbegin());
// }

// int main() {
//   assert(1 == scanf("%d", &N));
//   color.resize(N);
//   in_box.assign(N, false);

//   std::map<int, int> type_to_color;
//   for (int i = 0; i < N; ++i) {
//     int Ti;
//     assert(1 == scanf("%d", &Ti));
//     if (type_to_color.find(Ti) == type_to_color.end()) {
//       int new_color = type_to_color.size();
//       type_to_color[Ti] = new_color;
//       max_occurrences.insert(0);
//     }
//     color[i] = type_to_color[Ti];
//   }

//   color_occurrences.assign(type_to_color.size(), 0);

//   int answer = min_cardinality(N);
//   int Q = *std::max_element(op_counter.begin(), op_counter.end());
//   printf("%d\n", answer);
//   printf("%d\n", Q);
//   return 0;
// }

• Subtask 1: 0 / 10
• Subtask 2: 0 / 15
• Subtask 3: 0 / 75