Cod sursa(job #796342)

Utilizator claudiumihailClaudiu Mihail claudiumihail Data 11 octombrie 2012 09:25:44
Problema Sortare prin comparare Scor 80
Compilator cpp Status done
Runda Arhiva educationala Marime 1.88 kb
#include <fstream>
#include <iostream>
#include <vector>
#include <cstdlib>

using std::cout;
using std::endl;
using std::fstream;
using std::vector;

typedef unsigned long ulong;

#define MAXN 500001

ulong vec[MAXN];

int ChoosePivot(int start, int end)
{
    return start + std::rand()%(end-start);
}

int SwapAroundPivot(ulong vec[], int start, int end, int pivot)
{
    while (start <= pivot || pivot <= end)
    {
        while (start <= pivot && vec[start] <= vec[pivot])
        {
            start++;
        }
        
        if (start <= pivot && vec[start] > vec[pivot])
        {
            std::swap(vec[start], vec[pivot]);
            pivot = start;
            start++;
        }

        while (pivot <= end && vec[pivot] <= vec[end])
        {
            end--;
        }
        
        if (pivot <= end && vec[pivot] > vec[end])
        {
            std::swap(vec[end], vec[pivot]);
            pivot = end;
            end--;
        }
    }
    
    return pivot;
}

void QuickSort(ulong vec[], int start, int end)
{
    if (start < end)
    {
        int pivot = ChoosePivot(start, end);
        
        /*cout << "Start = " << start << endl;
        cout << "End = " << end << endl;
        cout << "Pivot = " << pivot << endl;*/
        
        pivot = SwapAroundPivot(vec, start, end, pivot);
        
        QuickSort(vec, start, pivot);
        QuickSort(vec, pivot+1, end);
    }
}

int main()
{
    int n;
    fstream fin("algsort.in", fstream::in);
    fstream fout("algsort.out", fstream::out);
    
    fin >> n;
    //cout << n << endl;
    
    for (int i=0; i<n; ++i)
    {
        fin >> vec[i];
    }
    fin.close();

    QuickSort(vec, 0, n-1);
    
    for (int i=0; i<n; ++i)
    {
        fout << vec[i] << ' ';
    }
    //fout << "\n";

    fout.close();
    return 0;
}