Submission #993598

#	Time	Username	Problem	Language	Result	Execution time	Memory
993598		abczz	Permutation (APIO22_perm)	C++17	100 / 100	25 ms	472 KiB

perm

#include "perm.h"
#include <iostream>
#define ll long long

using namespace std;

vector <int> base2(ll k) {
	vector <int> V;
	ll mxbit = 0, cnt = 0;
	for (int i=59; i>=0; --i) {
		if (k & (1LL<<i)) {
			mxbit = i;
			break;
		}
	}
	for (int j=0; j<mxbit; ++j) {
		if (k & (1LL<<j)) V.push_back(-1);
		V.push_back(++cnt);
	}
	ll x = V.size();
	for (auto &u : V) {
		if (u == -1) u = x--;
		--u;
	}
	return V;
}

vector <int> base3(ll k) {
	vector <int> V, U;
	ll cnt = 0;
	ll tmp = k;
	while (tmp) {
		U.push_back(tmp % 3);
		tmp /= 3;
	}
	for (int i=0; i+1<U.size(); ++i) {
		if (U[i] == 1) V.push_back(-1);
		V.push_back(cnt+2);
		if (U[i] == 2) V.push_back(-1);
		V.push_back(cnt+1);
		cnt += 2;
	}
	if (U.back() == 2) V.push_back(++cnt);
	ll x = V.size();
	for (auto &u : V) {
		if (u == -1) u = x--;
		--u;
	}
	return V;
}

vector<int> opt(ll k) {
	auto b2 = base2(k);
	auto b3 = base3(k);
	if (b2.size() < b3.size()) return b2;
	else return b3;
}

std::vector<int> construct_permutation(long long k)
{
	auto f = opt(k);
	if (k <= 100) return f;
	for (int b=5; b<=100; ++b) {
		vector <int> pref = {};
		if (k % b != 0) pref = opt((k % b) + 1);
		vector<int> bin = opt(b);
		vector<int> nx = opt(k/b);
		for (auto &u : nx) {
			u += (ll)bin.size();
		}
		for (auto &u : pref) {
			u += (ll)(bin.size() + nx.size());
		}
		if (f.size() > pref.size() + bin.size() + nx.size()) {
			f.clear();
			for (auto u : pref) f.push_back(u);
			for (auto u : bin) f.push_back(u);
			for (auto u : nx) f.push_back(u);
		}
	}
	/*for (auto u : f) cout << u << " ";
	cout << endl;*/
	return f;
}

Compilation message (stderr)

perm.cpp: In function 'std::vector<int> base3(long long int)':
perm.cpp:36:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   36 |  for (int i=0; i+1<U.size(); ++i) {
      |                ~~~^~~~~~~~~

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