Submission #602996

#	Time	Username	Problem	Language	Result	Execution time	Memory
602996		tutis	Permutation (APIO22_perm)	C++17	91.33 / 100	2 ms	340 KiB

perm

#include "perm.h"
using namespace std;
#include <iostream>
#include <random>
#include <functional>
#include <map>
using ll = long long;
std::vector<int> construct_permutation(long long k)
{
	if (k % 2 == 0)
	{
		vector<int>a = construct_permutation(k / 2);
		a.push_back((int)a.size());
		return a;
	}
	if (k % 2 == 1 && k > 1000)
	{
		vector<int>a = construct_permutation(k - 1);
		a.insert(a.begin(), (int)a.size());
		return a;
	}
	vector<int>ret = { -1};
	vector<ll>dp = {1};
	k--;
	while (k != 0)
	{
		int sz = (int)ret.size();
		for (int i = sz - 1; i >= 0; i--)
		{
			ll sum = 0;
			for (int j = 0; j < (int)ret.size(); j++)
				if (ret[j] < i)
					sum += dp[j];
			if (sum <= k)
			{
				k -= sum;
				dp.push_back(sum);
				for (int &j : ret)
					if (j >= i)
						j++;
				ret.push_back(i);
				break;
			}
		}
	}
	ret.erase(ret.begin());
	return ret;
}

• Subtask 1: 10 / 10
• Subtask 2: 81.333333333 / 90