Submission #669704

#	Time	Username	Problem	Language	Result	Execution time	Memory
669704		victor_gao	Sorting (IOI15_sorting)	C++17	16 / 100	1 ms	468 KiB

sorting

#include "sorting.h"
#include <bits/stdc++.h>
#define MAXN 200015
using namespace std;
int bk[MAXN],pos_bk[MAXN],pre[MAXN],pos_pre[MAXN];
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
    for (int i=0;i<N;i++){
        bk[i]=i; pos_bk[i]=i;
        pre[i]=S[i];  pos_pre[S[i]]=i;
    }
    for (int i=N-1;i>=0;i--){
        swap(bk[X[i]],bk[Y[i]]);
        pos_bk[bk[X[i]]]=X[i];
        pos_bk[bk[Y[i]]]=Y[i];
    }
    for (int i=0;i<N;i++){
        swap(pre[X[i]],pre[Y[i]]);
        pos_pre[pre[X[i]]]=X[i];
        pos_pre[pre[Y[i]]]=Y[i];
        swap(bk[X[i]],bk[Y[i]]);
        pos_bk[bk[X[i]]]=X[i];
        pos_bk[bk[Y[i]]]=Y[i];
        int now=i+1;
        /*
        cout<<"Now : ";
        for (int j=0;j<N;j++)
            cout<<pre[j]<<" \n"[j==N-1];
        cout<<"pos_pre : ";
        for (int j=0;j<N;j++)
            cout<<pos_pre[j]<<" \n"[j==N-1];
        cout<<"from back : ";
        for (int j=0;j<N;j++)
            cout<<bk[j]<<" \n"[j==N-1];
        cout<<"from back pos : ";
        for (int j=0;j<N;j++)
            cout<<pos_bk[j]<<" \n"[j==N-1];
        cout<<"swap "<<pos_pre[now]<<" "<<pos_bk[now]<<'\n';
        */
        P[i]=pos_pre[now]; Q[i]=pos_bk[now];
        swap(pre[pos_pre[now]],pre[pos_bk[now]]);
        pos_pre[pre[pos_pre[now]]]=pos_pre[now];
        pos_pre[pre[pos_bk[now]]]=pos_bk[now];
    }
    return N;
}

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:6:39: warning: unused parameter 'M' [-Wunused-parameter]
    6 | int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
      |                                   ~~~~^

• Subtask 1: 0 / 8
• Subtask 2: 0 / 12
• Subtask 3: 16 / 16
• Subtask 4: 0 / 18
• Subtask 5: 0 / 20
• Subtask 6: 0 / 26