Submission #286753

#	Time	Username	Problem	Language	Result	Execution time	Memory
286753		Ozy	Sorting (IOI15_sorting)	C++17	100 / 100	191 ms	26616 KiB

sorting

#include "sorting.h"
#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i = (a); i <= (b); i++)
#define debug(a) cout << #a << " = " << a << endl

int sum,largo,act,cont;
int seg,n,m,w,pas;
int s[200001],x[600001],y[600001],doble[200001],visitados[200001],id[200001];

bool checa(int pos) {

    rep(i,0,n-1) visitados[i] = 0;
    rep(i,0,n-1) doble[i] = s[i];
    rep(i,0,pos) swap(doble[x[i]],doble[y[i]]);

    sum = 0;
    rep(i,0,n-1) {
        if (visitados[i] == 0) {

            act = doble[i];
            largo = 0;
            visitados[i] = 1;

            while (act != i) {
                largo++;
                visitados[act] = 1;
                act = doble[act];
            }

            sum += largo;

        }
    }

    if (sum <= (pos+1)) return true;
    else return false;

}

void binaria(int ini, int fin) {
    int mitad;

    if (ini <= fin) {
        mitad = (ini+fin)/2;
        if (checa(mitad)) {
            seg = mitad;
            binaria(ini,mitad-1);
        }
        else binaria(mitad+1 ,fin);

    }
}

int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {

    rep(i,0,N-1) if (S[i] == i) cont++;
    
    if (cont == N) return 0;
    
    n = N;
    m = M;
    rep(i,0,N-1) s[i] = S[i];
    rep(i,0,M-1) x[i] = X[i];
    rep(i,0,M-1) y[i] = Y[i];

    binaria(0,M-1);

    rep(i,0,n-1) visitados[i] = 0;
    rep(i,0,n-1) doble[i] = s[i];
    rep(i,0,seg) swap(doble[x[i]],doble[y[i]]);

    //rep(i,0,n-1) cout << s[i] << ' ';
    //cout << endl;
    //rep(i,0,n-1) cout << doble[i] << ' ';
    //cout << endl;

    rep(i,0,n-1) id[doble[i]] = i;
    cont = 0;
    rep(i,0,n-1) {
        if (visitados[i] == 0) {

            act = doble[i];
            pas = doble[act];
            visitados[i] = 1;

            while (visitados[id[pas]] == 0) {

                P[cont] = act;
                Q[cont] = pas;
                cont++;

                visitados[id[pas]] = 1;
                act = pas;
                pas = doble[pas];
            }

        }
    }
    //debug(cont);
    //debug(seg);
    while (cont <= seg) {
        P[cont] = 0;
        Q[cont] = 0;
        cont++;
    }

    rep(i,0,n-1) id[s[i]] = i;
    rep(i,0,seg) {

        swap(id[ s[ x[i] ] ],id[ s[ y[i] ] ]);
        swap(s[x[i]], s[y[i]] );

        swap(s[ id [ P[i]] ], s[ id [Q[i]] ]);
        swap(id[ P[i] ], id[ Q[i] ]);
        P[i] = id[P[i]];
        Q[i] = id[Q[i]];

    }

    //rep(i,0,seg) cout << P[i] << ' ' << Q[i] << endl;

    seg++;
    //cerr << seg;
    return seg;
}

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