并归排序算法

　 //并归排序算法  
　1 static void Main(string[] args)
        {
            Random rd = new Random();
            int[] testData = new int[20];
            SetNewData(rd, testData);       //初始化测试数组
            Console.WriteLine("排序前");
            WriteDate(testData);           //输出排序前数组
            testData = Method(testData);    //数组排序
            Console.WriteLine("");
            Console.WriteLine("排序后");
            WriteDate(testData);            //输出排序后数组
            Console.Read();
        }

        private static int[] Method(int[] noMethodData)
        {
            int[] result = new int[noMethodData.Length];    //左侧数组
            int[] left, right, tempresult;                  //右侧数组

            left = new int[noMethodData.Length / 2];
            right = new int[noMethodData.Length / 2];
            tempresult = new int[noMethodData.Length];

            if (noMethodData.Length <= 1)
                return noMethodData;
            if (noMethodData.Length % 2 == 1)
            {
                right = new int[noMethodData.Length / 2 + 1];
            }
            for (int i = 0; i < noMethodData.Length; i++)
            {
                if (i < noMethodData.Length / 2)
                {
                    left[i] = noMethodData[i];              //左侧数组赋值
                }
                else
                {
                    right[i - noMethodData.Length / 2] = noMethodData[i];   //右侧数组赋值
                }
            }
            left = Method(left);                            //左侧数组递归 
            right = Method(right);                          //右侧数组递归
            result = SortMethod(left, right);//并归排序

            return result;
        }

        private static int[] SortMethod(int[] left, int[] right)
        {
            int left_index = 0;
            int right_index = 0;
            int restult_index = 0;
            int[] result = new int[left.Length + right.Length];
            //合并两个数组，直到一个数组的末尾
            while (left_index < left.Length && right_index < right.Length)
            {
                result[restult_index] = left[left_index];
                if (right[right_index] < left[left_index])
                {
                    result[restult_index] = right[right_index];
                    right_index++;
                }
                else
                {
                    left_index++;
                }
                restult_index++;
            }
            //将为合并到结果数组的数字添加到结果中
            int[] tempData = left;          //默认右侧合并完成,合并左侧
            int startIndex = left_index;    //设置合并启始位子
            if (left_index >= left.Length)  //如果左侧合并完成合并右侧
            {
                tempData = right;           //设在待合并数组为右侧数组
                startIndex = right_index;   //设置合并启始位子
            }
            for (; restult_index < result.Length; restult_index++)
            {
                result[restult_index] = tempData[startIndex];
                startIndex++;
            }
            return result;

        }

        private static void WriteDate(int[] data)
        {
            Console.WriteLine("Data:");
            for (int i = 0; i < data.Length; i++)
            {
                Console.Write(data[i].ToString() + " ");
                
            }
            Console.WriteLine();

        }
        
        private static void SetNewData(Random rd, int[] data)
        {
            for (int i = 0; i < data.Length; i++)
            {
                data[i] = rd.Next(1, 100);
                System.Threading.Thread.Sleep(10);
            }

        }