java学习之—并归排序

/**
 * 并归排序
 * Create by Administrator
 * 2018/6/26 0026
 * 下午 5:13
 **/
public class DArray {

    private long[] theArray;

    private  int nElens;

    public DArray(int max){
        theArray = new long[max];
        nElens = 0;
    }

    public void insert(long value){
        theArray[nElens] = value;
        nElens++;
    }

    public void display(){
        for (int i = 0; i < nElens; i++) {
            System.out.print(theArray[i] + " ");
        }
        System.out.println("");
    }

    public void mergeSort(){
        long[] workSpace = new long[nElens];
        recMergeSort(workSpace,0,nElens-1);
    }

    private void recMergeSort(long[] workSpace, int lowerBound, int upperBound) {
        if(lowerBound == upperBound){
            return;
        }else{
            int mid = (lowerBound+upperBound) / 2;
            recMergeSort(workSpace,lowerBound,mid);
            recMergeSort(workSpace,mid+1,upperBound);
            merge(workSpace,lowerBound,mid+1,upperBound);
        }
    }

    private void merge(long[] workSpace, int lowerBound1, int mid1, int upperBound) {
        int i = 0;
        int lowerBound = lowerBound1;
        int mid = mid1-1;
        int n = upperBound-lowerBound+1;

        while (lowerBound1 <= mid && mid1 <= upperBound){
            if(theArray[lowerBound1] < theArray[mid1]){
                workSpace[i++] = theArray[lowerBound1++];
            }else{
                workSpace[i++] = theArray[mid1++];
            }
        }

        while (lowerBound1 <= mid){
            workSpace[i++] = theArray[lowerBound1++];
        }

        while (mid1 <= upperBound){
            workSpace[i++] = theArray[mid1++];
        }

        for (i = 0; i< n; i++){
            theArray[lowerBound+i] = workSpace[i];
        }
    }

    public static void main(String[] args) {
        int maxSize = 100;
        DArray array;
        array = new DArray(maxSize);

        array.insert(64);
        array.insert(21);
        array.insert(65);
        array.insert(1);
        array.insert(44);
        array.insert(20);
        array.insert(8);
        array.insert(15);
        array.insert(90);
        array.insert(76);
        array.insert(45);
        array.insert(55);

        array.display();

        array.mergeSort();

        array.display();
    }

}