Submission #602970

#	Time	Username	Problem	Language	Result	Execution time	Memory
602970		tutis	Permutation (APIO22_perm)	C++17	10 / 100	419 ms	340 KiB

perm

#include "perm.h"
using namespace std;
#include <iostream>
#include <random>
#include <functional>
using ll = long long;
std::vector<int> construct_permutation(long long k)
{
	vector<int>ret = { -1};
	vector<ll>dp = {1};
	k--;
	while (k != 0)
	{
		vector<int>ret_ = ret;
		vector<ll>dp_ = dp;
		ll k_ = k;
		function<void(int)>dfs = [&](int l)
		{
			if (k < k_)
			{
				k_ = k;
				dp_ = dp;
				ret_ = ret;
			}
			if (l == 0)
				return;
			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);

					dfs(l - 1);

					k += sum;
					dp.pop_back();
					ret.pop_back();
				}
			}
		};
		dfs(3);
		ret = ret_;
		dp = dp_;
		k = k_;
	}
	ret.erase(ret.begin());
	return ret;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 90