/**
     * 快速排序
     * 遞歸
     */
    private void quickSort(List<StuInfo> stuInfosList, int left, int right) {
        if (left >= right) {
            return ;
        }
        int l = left;
        int r = right;
        //基準(zhǔn)值，取中間
        int key = stuInfosList.get(left).getSum();

        boolean flag=true;
        //交換容器
        StuInfo student;
        while (l != r) {

            if(flag){
                if(key<stuInfosList.get(r).getSum()){
                    student = stuInfosList.get(r);
                    stuInfosList.set(r, stuInfosList.get(l));
                    stuInfosList.set(l, student);
                    flag=false;
                }else{
                    r--;
                }
            }else {
                if (key>stuInfosList.get(l).getSum()){
                    student = stuInfosList.get(r);
                    stuInfosList.set(r, stuInfosList.get(l));
                    stuInfosList.set(l, student);
                    flag=true;
                }else {
                    l++;
                }
            }
        }
        quickSort(stuInfosList,left, r - 1);
        quickSort(stuInfosList, l + 1, right);
}

/**
     * 雙向冒泡排序
     */
    private void doubleBubbleSort(List<StuInfo> stuInfosList) {
        //設(shè)置一個(gè)交換容器
        StuInfo student;
        //左右指針
        int left = 0, right = stuInfosList.size() - 1;
        while (left < right) {
            for (int i = left + 1; i <= right; i++) {
                if (stuInfosList.get(left).getSum() < stuInfosList.get(i).getSum()) {
                    student = stuInfosList.get(i);
                    stuInfosList.set(i, stuInfosList.get(left));
                    stuInfosList.set(left, student);
                }
            }
            left++;
            for (int i = right; i >= left; i--) {
                if (stuInfosList.get(right).getSum() > stuInfosList.get(i).getSum()) {
                    student = stuInfosList.get(i);
                    stuInfosList.set(i, stuInfosList.get(right));
                    stuInfosList.set(right, student);
                }
            }
            right--;
        }
    }

/**
     * 堆排序
     */
    private void heapSort(List<StuInfo> stuInfosList) {
        //建堆
        buildHeap(stuInfosList);
        StuInfo student;
        for (int i = stuInfosList.size() - 1; i >= 1; i--) {
            //交換
            student = stuInfosList.get(i);
            stuInfosList.set(i, stuInfosList.get(0));
            stuInfosList.set(0, student);
            //堆調(diào)整
            heapfity(stuInfosList, 0, i - 1);
        }
    }

    /**
     * 堆調(diào)整
     */
    private void heapfity(List<StuInfo> stuInfosList, int index, int len) {
        int lchild = index * 2 + 1;
        int rchild = index * 2 + 2;

        StuInfo student;
        int temp = 0;

        if (lchild <= len && rchild <= len) {
            temp = stuInfosList.get(lchild).getSum() < stuInfosList.get(rchild).getSum() ? lchild : rchild;
        } else if (lchild <= len) {
            temp = lchild;
        } else if (rchild <= len) {
            temp = rchild;
        }
        //
        if (stuInfosList.get(temp).getSum() < stuInfosList.get(index).getSum()) {
            student = stuInfosList.get(temp);
            stuInfosList.set(temp, stuInfosList.get(index));
            stuInfosList.set(index, student);
        }
    }

    /**
     * 建立小根堆
     */
    private void buildHeap(List<StuInfo> stuInfosList) {
        for (int i = stuInfosList.size() / 2 - 1; i >= 0; i--) {
            heapfity(stuInfosList, i, stuInfosList.size() - 1);
        }
    }

/**
     * 希爾排序
     */
    private void shellSort(List<StuInfo> stuInfosList) {

        int step = stuInfosList.size() / 2;
        while (step >= 1) {

            for (int start = 0; start < step; start++) {
                insertSort(stuInfosList, step, start);
            }
            step /= 2;
        }
    }

    /**
     * 希爾排序循環(huán)內(nèi)使用的插入排序
     */
    private void insertSort(List<StuInfo> stuInfosList, int step, int start) {
        //交換容器
        StuInfo student;
        for (int i = start + step; i < stuInfosList.size(); i += step) {
            for (int j = i; j - step >= 0 && stuInfosList.get(j).getSum() > stuInfosList.get(j - step).getSum(); j -= step) {
                student = stuInfosList.get(j);
                stuInfosList.set(j, stuInfosList.get(j - step));
                stuInfosList.set(j - step, student);
            }
        }
}