Cod sursa(job #2296250)

Utilizator adimiclaus15Miclaus Adrian Stefan adimiclaus15 Data 4 decembrie 2018 16:19:55
Problema Sortare prin comparare Scor 0
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.46 kb
#include <iostream>//3 pivoti random din care aleg mediana
#include <ctime>
#include <cstdlib>
#include <fstream>
using namespace std;
ifstream f("algsort.in");
ofstream g("algsort.out");
int n,a[500001];
int partitionare(int st,int dr)
{
    int i,j,pivot,r1,r2,r3,minim,maxim;
    //swap(a[st+rand()%(dr-st+1)],a[dr]);
    r1=st+rand()%(dr-st+1);
    r2=st+rand()%(dr-st+1);
    r3=st+rand()%(dr-st+1);
    minim=r1;
    if(a[minim]>a[r2])
    {
        minim=r2;
    }
    if(a[minim]>a[r3])
    {
        minim=r3;
    }
    maxim=r1;
    if(a[maxim]<a[r2])
    {
        maxim=r2;
    }
    if(a[maxim]<a[r3])
    {
        maxim=r3;
    }
    if(r1!=minim && r1!=maxim)
    {
        swap(a[r1],a[dr]);
    }
    if(r2!=minim && r2!=maxim)
    {
        swap(a[r2],a[dr]);
    }
    if(r3!=minim && r3!=maxim)
    {
        swap(a[r3],a[dr]);
    }
    pivot=a[dr];
    j=st-1;
    for(i=st;i<=dr;i++)
    {
        if(a[i]<=pivot)
        {
            j++;
            swap(a[i],a[j]);
        }
    }
    return j;
}
void QuickSort(int st,int dr)
{
    int poz;
    poz=partitionare(st,dr);
    if(st<poz-1)
    {
        QuickSort(st,poz-1);
    }
    if(dr>poz+1)
    {
        QuickSort(poz+1,dr);
    }
}
int main()
{
    int i;
    srand(time(NULL));
    f>>n;
    for(i=1;i<=n;i++)
    {
        f>>a[i];
    }
    QuickSort(1,n);
    for(i=1;i<=n;i++)
        cout<<a[i]<<" ";
    return 0;
}