Submission #574170

#	Time	Username	Problem	Language	Result	Execution time	Memory
574170		Lawliet	Permutation (APIO22_perm)	C++17	92.67 / 100	3 ms	340 KiB

perm

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

using namespace std;

vector<int> buildBaseTwo(long long k)
{
	int mn = 0;
	vector<int> ans;

	while( k > 1 )
	{
		if( k & 1 )
			ans.push_back( mn++ ), k ^= 1;
		else
			ans.push_back( -1 ), k >>= 1;
	}

	int mx = (int)ans.size() - 1;

	for(int i = 0 ; i < ans.size() ; i++)
		if( ans[i] == -1 ) ans[i] = mx--;

	reverse( ans.begin() , ans.end() );
	return ans;
}

vector<int> buildBaseThree(long long k)
{
	int mn = 0;
	vector<int> ans;

	while( k > 2 )
	{
		if( k%3 == 1 )
			ans.push_back( mn++ ), k--;
		else if( k%3 == 2 )
			ans.insert( ans.end() , { mn , mn + 1 } ), k -= 2, mn += 2;
		else
			ans.insert( ans.end() , { -1 , -1 } ), k /= 3;
	}

	if( k == 2 )
		ans.push_back( mn++ );

	int mx = (int)ans.size() - 1;

	for(int i = 0 ; i < ans.size() ; i++)
		if( ans[i] == -1 ) ans[i + 1] = mx--, ans[i] = mx--;

	reverse( ans.begin() , ans.end() );

	return ans;
}

vector<int> construct_permutation(long long k)
{
	vector<int> bTwo = buildBaseTwo(k);
	vector<int> bThree = buildBaseThree(k);

	if( bTwo.size() <= bThree.size() )
		return bTwo;

	return bThree;
}

Compilation message (stderr)

perm.cpp: In function 'std::vector<int> buildBaseTwo(long long int)':
perm.cpp:21:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   21 |  for(int i = 0 ; i < ans.size() ; i++)
      |                  ~~^~~~~~~~~~~~
perm.cpp: In function 'std::vector<int> buildBaseThree(long long int)':
perm.cpp:48:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 |  for(int i = 0 ; i < ans.size() ; i++)
      |                  ~~^~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 82.666666665 / 90