Submission #60162

#	Time	Username	Problem	Language	Result	Execution time	Memory
60162		dukati8	Sorting (IOI15_sorting)	C++14	100 / 100	468 ms	15592 KiB

sorting

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

vector<pair<int, int> > moves;
int movestofix(int Ii[],int Ss[], int N) {
  int I[N], S[N];
  rep (i,0,N) { I[i]=Ii[i];S[i]=Ss[i];}
  moves.clear();
  //I[i] is not value at i, but index of value i in S
  int counter=0;
  rep(i,0,N) {
    if (S[i]==i) continue;
    counter++;
    int a,b;
    a=i;
    b=I[i];
    //a och b byter plats
    int sa,sb;
    sa=S[a];
    sb=S[b];
    moves.push_back(make_pair(a,b));
    S[a]=sb;
    S[b]=sa;
    I[sa]=b;
    I[sb]=a;

  }
  moves.push_back(make_pair(0,0));
  return counter;
}

int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
  int I[N];
  rep (i,0,N) {
    I[S[i]]=i;
  }
  int i=0;
  int hi,lo;
  hi=N;
  lo=-1;
  while (hi>lo+1) {
    int mid=(hi+lo)/2;
    int copyI[N],copyS[N];
    rep (x,0,N) {
      copyI[x]=I[x];
      copyS[x]=S[x];
    }
    rep (x,0,mid) {
      int a,b;
      a=X[x];
      b=Y[x];
      //a och b byter plats
      int sa,sb;
      sa=copyS[a];
      sb=copyS[b];
      copyS[a]=sb;
      copyS[b]=sa;
      copyI[sa]=b;
      copyI[sb]=a;
    }
    if (movestofix(copyI,copyS,N)>mid) lo=mid;
    else hi=mid;
  }
  i=hi;
  int mid = hi;
  int copyI[N],copyS[N];
  rep (x,0,N) {
    copyI[x]=I[x];
    copyS[x]=S[x];
  }
  rep (x,0,mid) {
    int a,b;
    a=X[x];
    b=Y[x];
    //a och b byter plats
    int sa,sb;
    sa=copyS[a];
    sb=copyS[b];
    copyS[a]=sb;
    copyS[b]=sa;
    copyI[sa]=b;
    copyI[sb]=a;
  }
  if (movestofix(copyI,copyS,N)>mid) lo=mid;
  else hi=mid;

  rep (j,0,N) {S[j]=j;I[j]=j;}

  for (int j=i-1;j>=0; j--) {
    P[j]=S[moves[j].first];
    Q[j]=S[moves[j].second];
    //swap(switches[X[j]],switches[Y[j]]);
    int a,b;
    a=I[X[j]];
    b=I[Y[j]];
    //a och b byter plats
    int sa,sb;
    sa=S[a];
    sb=S[b];
    S[a]=sb;
    S[b]=sa;
    I[sa]=b;
    I[sb]=a;
  }
  return i;
}

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:34:39: warning: unused parameter 'M' [-Wunused-parameter]
 int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
                                       ^

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