Submission #419250

#	Time	Username	Problem	Language	Result	Execution time	Memory
419250		Mounir	Sorting (IOI15_sorting)	C++14	100 / 100	194 ms	16476 KiB

sorting

#include "sorting.h"
#include <bits/stdc++.h>
#define sz(x) (int)x.size()
#define chmax(x, v) x = max(x, v)
#define chmin(x, v) x = min(x, v)
#define all(x) x.begin(), x.end()
#define pb push_back
#define pii pair<int, int>
#define x first
#define y second
using namespace std;

const int N_VALS = 1e6;

int nVals, nTours;
vector<int> vals, tmp;
vector<pii> modifs;
bool vu[N_VALS];

int nCycles(){
	for (int ind = 0; ind < nVals; ++ind)
		vu[ind] = false;
	
	int nb = 0;
	
	//cout << "BEGIN" << endl;

	for (int depart = 0; depart < nVals; ++depart){
		if (!vu[depart]){
			nb++;

			vu[depart] = true;
			int noeud = vals[depart];
			while (noeud != depart){
				vu[noeud] = true;
				noeud = vals[noeud];
			}
		}
	}

	//cout << "END" << endl;

	return nb;
}

void faireSwaps(int borneMax){
	for (int ind = 0; ind < nVals; ++ind)
		vals[ind] = tmp[ind];
	for (int ind = 1; ind <= borneMax; ++ind)
		swap(vals[modifs[ind].x], vals[modifs[ind].y]);
}

int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
    //initialisation.
    nVals = N, nTours = M;
    vals.resize(nVals), tmp.resize(nVals);
    for (int ind = 0; ind < nVals; ++ind)
    	vals[ind] = tmp[ind] = S[ind];

    modifs.resize(nTours + 1);
    for (int ind = 0; ind < nTours; ++ind)
    	modifs[ind + 1] = {X[ind], Y[ind]};


    //Dichotomie pour trouver R.
    int gauche = 0, droite =  nTours + 1; //vu que la fin est exclue
    while (droite > gauche){
    	int milieu = (droite + gauche)/2;
    	faireSwaps(milieu);

    //	cout << "m " << milieu << " " << nCycles() << endl;

    	if (milieu >= nVals - nCycles())
    		droite = milieu;
    	else
    		gauche = milieu + 1;
    //	cout << gauche << " " << droite << endl;
    }

    

    int res = droite;
    faireSwaps(res); 

    vector<int> p, q;
/*
    for (int val : vals)
    	cout << val << " ";
    cout << endl;
*/
    int nb = 0;
    for (int ind = 0; ind < nVals; ++ind){
    	while (vals[ind] != ind){
    		p.pb(ind);
    		q.pb(vals[ind]);
    		swap(vals[ind], vals[vals[ind]]);
    		nb++;
    	}
    }

    while (nb < res){
 		p.pb(0);
 		q.pb(0);
 		nb++;
    }
/*
 	for (int ind = 0; ind < res; ++ind)
 		cout << p[ind] << " " << q[ind] << endl;
*/


    vector<int> permutation(nVals);
    for (int ind = 0; ind < nVals; ++ind)
    	permutation[ind] = ind;

    for (int iModif = res; iModif >= 2; --iModif){
    	swap(vals[permutation[modifs[iModif].x]], vals[permutation[modifs[iModif].y]]);
    	swap(permutation[modifs[iModif].x], permutation[modifs[iModif].y]);
    	p[iModif - 2] = vals[p[iModif - 2]];
    	q[iModif - 2] = vals[q[iModif - 2]];             
    }


    for (int ind = 0; ind < res; ++ind){
    	P[ind] = p[ind];
    	Q[ind] = q[ind];
    }
/*
    for (int ind = 0; ind < res; ++ind){
    	P[ind] = P[ind + 1];
    	Q[ind] = Q[ind + 1];
    }
*/

   // cout << endl;//
//    cout << "SALUT\n";
   for (int ind = 0; ind < res; ++ind){
    //	cout << "TOUR\n";
  //  	cout << X[ind] << " " << Y[ind] << endl;
    //	cout << P[ind] << " " << Q[ind] << endl;
    	swap(vals[X[ind]], vals[Y[ind]]);
    	swap(vals[P[ind]], vals[Q[ind]]);

    	/*for (int val : vals)
    		cout << val << " ";
    	cout << endl;*/
    }


	return res;
}

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