Submission #825313

#	Time	Username	Problem	Language	Result	Execution time	Memory
825313		esomer	Prisoner Challenge (IOI22_prison)	C++17	5 / 100	11 ms	19156 KiB

prison

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

using namespace std;

typedef long long ll;

int N;
vector<vector<int>> ans;
vector<int> dp, which;

void build(int ind, int l, int r) {
	int total = r - l + 1;
	if(total <= 2){
		// cout << "ind " << ind << " total " << total << " l " << l << " r " << r << endl;
		for(int i = 1; i <= N; i++){
			if(i < l){
				ans[ind][i] = -(ans[ind][0] + 1);
			}else if(i > r){
				ans[ind][i] = -((1 - ans[ind][0]) + 1);
			}else if(i == l){
				ans[ind][l] = -(ans[ind][0] + 1);
			}else if(i == r) {
				ans[ind][r] = -((1 - ans[ind][0]) + 1);
			}
		// cout << "ind "<< ind << " i " << i << " " << ans[ind][i] << endl;
		}
		return;
	}
	int x = which[total];
	total -= 2;
	vector<int> sizes(x, total / x);
	for(int i = 0; i < total % x; i++){
		sizes[i]++;
	}
	while((int)sizes.size() > 0 && sizes.back() == 0) sizes.pop_back();
	// cout << "ind " << ind << " x " << x << " total " << total << endl;
	int curr = 0;
	int cind = 0;
	for(int i = 1; i <= N; i++){
		if(i < l){
			ans[ind][i] = -(ans[ind][0] + 1);
		}else if(i > r){
			ans[ind][i] = -((1 - ans[ind][0]) + 1);
		}else if(i == l){
			ans[ind][l] = -(ans[ind][0] + 1);
		}else if(i == r) {
			ans[ind][r] = -((1 - ans[ind][0]) + 1);
		}else{
			curr++;
			ans[ind][i] = (int)ans.size();
			if(curr == sizes[cind]){
				ans.push_back({}); ans[(int)ans.size() - 1].resize(N+1);
				ans[(int)ans.size() - 1][0] = 1 - ans[ind][0];
				build((int)ans.size() - 1, i - curr + 1, i);
				curr = 0; cind++;
			}
		}
		// cout << "ind "<< ind << " i " << i << " " << ans[ind][i] << endl;
	}
}

void calc_dp(){
	dp.assign(N+1, 1e9);
	which.assign(N+1, 1);
	for(int i = 0; i <= N; i++){
		int real = i - 2;
		if(real <= 0) dp[i] = 0;
		else{
			for(int x = 1; x <= 20; x++){
				int cll = real / x;
				if(real % x != 0) cll++;
				int needed = x + dp[cll]; 
				if(needed < dp[i]){
					which[i] = x;
					dp[i] = needed;
				}
			}
		}
	}
}

vector<vector<int>> devise_strategy(int n) {
	N = n;
	calc_dp();
	ans.push_back({}); ans[0].resize(N+1);
	ans[0][0] = 0;
	build(0, 1, N);
	return ans;
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 5
• Subtask 3: 0 / 90