Submission #345683

#	Time	Username	Problem	Language	Result	Execution time	Memory
345683		ogibogi2004	Sorting (IOI15_sorting)	C++14	100 / 100	209 ms	32456 KiB

sorting

#include "sorting.h"
#include <bits/stdc++.h>
using namespace std;
const int MAXN=2e5+6;
vector<pair<int,int> >swaps;
int seq[MAXN],seq1[MAXN],seq2[MAXN];
bool vis[MAXN];
int where[MAXN];
int n;
vector<pair<int,int> >moves;
bool check(int x)
{
	for(int i=0;i<n;i++)
	{
		seq2[i]=seq[i];
	}
	for(int j=0;j<x&&j<swaps.size();j++)
	{
		swap(seq2[swaps[j].first],seq2[swaps[j].second]);
	}
	int cnt=0;
	memset(vis,0,sizeof(vis));
	moves.clear();
	/*cout<<x<<":";
	for(int i=0;i<n;i++)
	{
		cout<<seq1[i]<<" ";
	}
	cout<<endl;*/
	/*for(int i=0;i<n;i++)cout<<seq2[i]<<" ";
	cout<<endl;*/
	for(int i=0;i<n;i++)
	{
		if(seq2[i]!=i)
		{
			int u=i;
			for(;;)
			{
				int j=seq2[i];
				moves.push_back({seq2[i],seq2[j]});
				//cout<<i<<" "<<j<<endl;
				//cout<<seq2
				swap(seq2[i],seq2[j]);
				if(seq2[i]==i)break;
			}
			//swap(seq2[i],seq2[u]);
			cnt++;
			//moves.pop_back();
		}
	}
	//cout<<endl;
	//cout<<x<<" "<<cnt<<endl;
	if(moves.size()<=x)
	{
		while(moves.size()<x)moves.push_back({0,0});
		return 1;
	}
	else return 0;
}
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
    n=N;
    for(int i=0;i<n;i++)seq[i]=S[i];
    for(int i=0;i<M;i++)swaps.push_back({X[i],Y[i]});
    int low=0,high=M,mid,ans;
    while(low<=high)
    {
		mid=(low+high)/2;
		if(check(mid))
		{
			ans=mid;
			high=mid-1;
		}
		else low=mid+1;
	}
	//cout<<ans<<endl;
	check(ans);
	for(int i=0;i<N;i++)
	{
		where[S[i]]=i;
	}
	/*for(int i=0;i<moves.size();i++)
	{
		cout<<moves[i].first<<" "<<moves[i].second<<endl;
	}*/
	for(int i=0;i<moves.size();i++)
	{
		int w1=S[X[i]],w2=S[Y[i]];
		swap(S[X[i]],S[Y[i]]);
		swap(where[w1],where[w2]);
		P[i]=where[moves[i].first];
		Q[i]=where[moves[i].second];
		swap(where[moves[i].first],where[moves[i].second]);
		swap(S[P[i]],S[Q[i]]);
		/*cout<<i<<":\n";
		for(int j=0;j<n;j++)
		{
			cout<<S[j]<<" ";
		}
		cout<<endl;
		for(int j=0;j<n;j++)
		{
			cout<<where[j]<<" ";
		}
		cout<<endl;*/
	}
	/*for(int i=0;i<moves.size();i++)
	{
		P[i]=moves[i].first;Q[i]=moves[i].second;
	}*/
	return moves.size();
}

Compilation message (stderr)

sorting.cpp: In function 'bool check(int)':
sorting.cpp:17:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 |  for(int j=0;j<x&&j<swaps.size();j++)
      |                   ~^~~~~~~~~~~~~
sorting.cpp:36:8: warning: unused variable 'u' [-Wunused-variable]
   36 |    int u=i;
      |        ^
sorting.cpp:53:17: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   53 |  if(moves.size()<=x)
      |     ~~~~~~~~~~~~^~~
sorting.cpp:55:21: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   55 |   while(moves.size()<x)moves.push_back({0,0});
      |         ~~~~~~~~~~~~^~
sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:85:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   85 |  for(int i=0;i<moves.size();i++)
      |              ~^~~~~~~~~~~~~
sorting.cpp:110:19: warning: conversion from 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} to 'int' may change value [-Wconversion]
  110 |  return moves.size();
      |         ~~~~~~~~~~^~
sorting.cpp:76:7: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
   76 |  check(ans);
      |  ~~~~~^~~~~

• Subtask 1: 8 / 8
• Subtask 2: 12 / 12
• Subtask 3: 16 / 16
• Subtask 4: 18 / 18
• Subtask 5: 20 / 20
• Subtask 6: 26 / 26