C# 算法之选择排序

    /// <summary>
    /// 选择排序
    /// </summary>
    public class SelectctionSort
    {
        static void Main(string[] args)
        {
            var arr = new IComparable[] { 7,3,5,1,2,89,8 };
            var result= Sorted(arr);
            Array.ForEach(arr, Console.WriteLine);
            Console.WriteLine("排序是否成功?{0}", IsSorted(result) ? "是" : "否");
            Console.ReadKey();
        }

        /// <summary>
        /// 选择排序Main方法
        /// </summary>
        /// <param name="array"></param>
        /// <returns></returns>
        public static IComparable[] Sorted(IComparable[] array)
        {
            int count = array.Length;
            for (int i = 0; i < count; i++)
            {
                //假设每一轮外循环的第一个是最小的
                int min = i;
                for (int j = i + 1; j < count; j++)
                    if (Less(array[j], array[min])) min = j;
                Exchange(array, i, min);
            }
            return array;
        }

        /// <summary>
        /// 判断两个元素的大小
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <returns></returns>
        private static bool Less(IComparable a, IComparable b)
        {
            var res = a.CompareTo(b);
            return res < 0;
        }

        /// <summary>
        /// 交换一轮循环后的结果
        /// </summary>
        /// <param name="array"></param>
        /// <param name="i"></param>
        /// <param name="min"></param>
        private static void Exchange(IComparable[] array,int i,int min)
        {
            var temp = array[i];
            array[i] = array[min];
            array[min] = temp;
        }

        /// <summary>
        /// 判断排序是否正确
        /// </summary>
        /// <param name="array"></param>
        /// <returns></returns>
        private static bool IsSorted(IComparable[] array)
        {
            for (int i = 1; i < array.Length; i++)
            {
                if (Less(array[i], array[i-1])) return false;
            }
            return true;
        }
    }