Submission #1019275

#	Time	Username	Problem	Language	Result	Execution time	Memory
1019275		parsadox2	Sorting (IOI15_sorting)	C++17	100 / 100	123 ms	34752 KiB

sorting

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

using namespace std;

#define F first
#define S second

const int N = 2e5 + 10 , M = 6e5 + 10;
int n , ar[N] , pos[N] , m , L[M] , R[M] , f[M] , s[M];
vector <pair<int , int>> vec;

bool Check(int mid)
{
	for(int i = 0 ; i < mid ; i++)
		swap(ar[L[i]] , ar[R[i]]);
	for(int i = 0 ; i < n ; i++)
		pos[ar[i]] = i;
	vec.clear();
	for(int i = 0 ; i < n ; i++)  if(ar[i] != i)
	{
		int p = pos[i];
		swap(ar[i] , ar[p]);
		pos[ar[p]] = p;
		pos[ar[i]] = i;
		vec.push_back(make_pair(ar[i] , ar[p]));
	}
	return (vec.size() <= mid);
}

void Solve(int mid)
{
	if(vec.size() < mid)
		vec.push_back(make_pair(0 , 0));
	for(int i = 0 ; i < mid ; i++)
	{
		swap(ar[L[i]] , ar[R[i]]);
		swap(pos[ar[L[i]]] , pos[ar[R[i]]]);
		f[i] = pos[vec[i].F];
		s[i] = pos[vec[i].S];
		swap(ar[f[i]] , ar[s[i]]);
		swap(pos[ar[f[i]]] , pos[ar[s[i]]]);
	}
}

int findSwapPairs(int nn, int S[], int mm, int X[], int Y[], int P[], int Q[]) {
	n = nn;
	m = mm;
	for(int i = 0 ; i < m ; i++)
	{
		L[i] = X[i];
		R[i] = Y[i];
	}
	int low = -1 , high = m;
	while(high - low > 1)
	{
		for(int i = 0 ; i < n ; i++)
		{
			ar[i] = S[i];
			pos[ar[i]] = i;
		}
		int mid = (low + high) >> 1;
		if(Check(mid))
			high = mid;
		else
			low = mid;
	}
	for(int i = 0 ; i < n ; i++)
	{
		ar[i] = S[i];
		pos[ar[i]] = i;
	}
	Check(high);
	for(int i = 0 ; i < n ; i++)
	{
		ar[i] = S[i];
		pos[ar[i]] = i;
	}
	Solve(high);
	for(int i = 0 ; i < m ; i++)
	{
		P[i] = f[i];
		Q[i] = s[i];
	}
	return high;
}

Compilation message (stderr)

sorting.cpp: In function 'bool Check(int)':
sorting.cpp:28:21: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   28 |  return (vec.size() <= mid);
      |          ~~~~~~~~~~~^~~~~~
sorting.cpp: In function 'void Solve(int)':
sorting.cpp:33:16: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   33 |  if(vec.size() < mid)
      |     ~~~~~~~~~~~^~~~~

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