private void button2_Click(object sender, EventArgs e)
        {
            SqListClass L4 = new SqListClass();

            Merge3(ref L4);
            textBox4.Text = L4.DispList();
        }
        private void comboBox1_SelectedIndexChanged_1(object sender, EventArgs e)
        {
            int k = comboBox1.SelectedIndex;                  //使用combobox中的索引号来判断要执行什么操作

            if (k == 0)
            {
                textBox2.Enabled = false;
                label3.Text      = "长度";
                textBox3.Text    = L.ListLength().ToString();
            }
            else if (k == 1)
            {
                textBox2.Enabled = true;
                label3.Text      = "序号";
                label4.Text      = "元素";
                Findele();
            }
            else if (k == 2)
            {
                textBox2.Enabled = true;
                label3.Text      = "元素";
                label4.Text      = "序号";
                Findnum();
            }
            else if (k == 3)
            {
                textBox2.Enabled = true;
                label3.Text      = "序号";
                label4.Text      = "元素";
                Insert();
            }
            else if (k == 4)
            {
                textBox2.Enabled = true;
                string text3 = textBox3.Text.ToString();
                string text2 = textBox2.Text.ToString();
                label3.Text = "按序号";
                label4.Text = "按元素";
                if (text3 != "" && text2 == "")
                {
                    Deletebynum();
                }
                else if (text3 == "" && text2 != "")
                {
                    Deletebyele(text2);
                }
            }
            else if (k == 5)
            {
                textBox2.Enabled = true;
                SqListClass L1 = new SqListClass();
                SqListClass L2 = new SqListClass();
                Split(ref L1, ref L2);
                label3.Text   = "奇数序号的元素";
                label4.Text   = "偶数序号的元素";
                textBox3.Text = L1.DispList();
                textBox2.Text = L2.DispList();
            }
        }
        private void Merge3(ref SqListClass L4)         //三路归并
        {
            int i = 0, j = 0, k = 0, s = 0, t;
            int a, b, c, mind = 0;

            while (i < L1.length || j < L2.length || k < L3.length)
            {
                if (i >= L1.length)
                {
                    a = INF;
                }
                else
                {
                    a = Convert.ToInt16(L1.data[i]);
                }
                if (j >= L2.length)
                {
                    b = INF;
                }
                else
                {
                    b = Convert.ToInt16(L2.data[j]);
                }
                if (k >= L3.length)
                {
                    c = INF;
                }
                else
                {
                    c = Convert.ToInt16(L3.data[k]);
                }
                t = mindata(a, b, c, ref mind);
                switch (t)
                {
                case 1: L4.data[s] = mind.ToString();
                    s++;
                    i++;
                    break;

                case 2: L4.data[s] = mind.ToString();
                    s++;
                    j++;
                    break;

                case 3: L4.data[s] = mind.ToString();
                    s++;
                    k++;
                    break;
                }
            }
            L4.length = s;
        }
        private void Split(ref SqListClass L1, ref SqListClass L2)           //建立奇偶顺序表表
        {
            int    i = 1, j = 1, k = 1;
            string x = "";

            while (k <= L.ListLength())
            {
                L.GetElem(k, ref x);
                L1.ListInsert(i, x);
                i++;
                k++;
                if (k <= L.ListLength())
                {
                    L.GetElem(k, ref x);
                    L2.ListInsert(j, x);
                    j++;
                    k++;
                }
            }
            label2.Text = "成功产生两个顺序表";
        }