Tutoring-APCompSci/Sorting/QuickSorter.java

package Sorting;

public class QuickSorter extends NumberSorter{
    
    public QuickSorter(RandomNumberFileReader reader){
        super("quick sort", reader);
    }

    public QuickSorter(String qsortVariant, RandomNumberFileReader reader){
        super(qsortVariant, reader);
    }

    void sort(){
        quickSort(0,numbers.length-1);
    }

    void quickSort(int lowIndex, int highIndex){
       if(compare(lowIndex,highIndex)<0){
            int pivot = partition(lowIndex, highIndex);
            quickSort(lowIndex, pivot-1);
            quickSort(pivot+1, highIndex);
       }
    }

    private int partition(int lowIndex, int highIndex){
        int pivot = numbers[highIndex];
        int i = lowIndex-1;
        for(int j=lowIndex;j<highIndex;j++){
            if(compare(numbers[j],pivot)<0){
                i++;
                swap(i,j);
            }
        }
        swap(i+1, highIndex);
        return i+1;
    }

}