c# .Net 常见算法

  1 using System.Collections.Generic;
  2 using System.ComponentModel.Design;
  3 using System.Linq;
  4 
  5 namespace TestDelay
  6 {
  7     internal class Program
  8     {
  9         static void Main()
 10         {
 11             int[] arry = new int[] { 12, 32, 434, 56, 2, 1, 9, 0 };
 12             BubbleSort(arry);
 13             Console.WriteLine("冒泡排序：" + string.Join(",", arry));
 14 
 15             Demo1(7);
 16             Reverse("I am a good man");
 17 
 18             Demo2(4);
 19 
 20             Demo3(30);
 21         }
 22         /// <summary>
 23         /// 冒泡排序
 24         /// </summary>
 25         /// <param name="arry"></param>
 26         public static void BubbleSort(int[] arry)
 27         {
 28             for (int i = 0; i < arry.Length - 1; i++)
 29             {
 30                 for (int j = i + 1; j < arry.Length; j++)
 31                 {
 32                     if (arry[i] > arry[j])
 33                     {
 34                         var temp = arry[i];
 35                         arry[i] = arry[j];
 36                         arry[j] = temp;
 37                     }
 38                 }
 39             }
 40         }
 41 
 42         /// 求以下表达式的值，写出您想到的一种或几种实现方法： 1-2+3-4+……+m
 43         /// 拆分为(1-2)+(3-4)+(5-6)+...+m
 44         /// </summary>
 45         /// <param name="m"></param>
 46         public static void Demo1(int m)
 47         {
 48             #region 第一种方式
 49             int result1 = 0;
 50             if (m % 2 == 0)
 51                 result1 = -(m / 2);
 52             else
 53                 result1 = -(m - 1) / 2 + m;
 54             #endregion
 55             #region 第二种方式
 56             int result2 = 0;
 57             for (int i = 1; i <= m; i++)
 58             {
 59                 if (i % 2 == 0)
 60                     result2 = result2 - i;
 61                 else
 62                     result2 = result2 + i;
 63             }
 64             #endregion
 65             Console.WriteLine(result1 == result2);
 66         }
 67 
 68         /// <summary>
 69         /// 有一个字符串 "I am a good man",设计一个函数,返回 "man good a am I"。
 70         /// </summary>
 71         /// <param name="str"></param>
 72         public static void Reverse(string str)
 73         {
 74             var strArry = str.Split(" ");
 75             var result1 = string.Join(" ", strArry.Reverse());
 76             List<string> list = new List<string>();
 77             for (int i = strArry.Length - 1; i >= 0; i--)
 78             {
 79                 list.Add(strArry[i]);
 80             }
 81             var result2 = string.Join(" ", list);
 82             Console.WriteLine(result1 == result2);
 83         }
 84 
 85         /// <summary>
 86         /// 有1、2、3、4个数字,能组成多少个互不相同且无重复数字的三位数?都是多少?
 87         /// </summary>
 88         /// <param name="number"></param>
 89         public static void Demo2(int number)
 90         {
 91             List<string> list = new List<string>();
 92             for (int b = 1; b <= number; b++)
 93             {
 94                 for (int s = 1; s <= number; s++)
 95                 {
 96                     if (b != s)
 97                     {
 98                         for (int g = 1; g <= number; g++)
 99                         {
100                             if (b != s && b != g && s != g)
101                                 list.Add($"{b}{s}{g}");
102                         }
103                     }
104                 }
105             }
106             Console.WriteLine($"1-{number},共有：{list.Count}个不重复三位数，分别是：{string.Join(",", list)}");
107         }
108 
109 
110         /// <summary>
111         /// 1、1、2、3、5、8、13、21、34，....⽤C#递归写出算法，算出第30个数。
112         /// </summary>
113         /// <param name="number"></param>
114         public static void Demo3(int number)
115         {
116             List<int> list= new List<int>();
117             Recursion(0, list);
118             var result = string.Join(" ", list);
119         }
120         /// <summary>
121         /// 1、1、2、3、5、8、13、21、34，....⽤C#递归写出算法，算出第30个数
122         /// </summary>
123         /// <param name="number"></param>
124         /// <param name="list"></param>
125         public static void Recursion(int number, List<int> list)
126         {
127             if (number <= 1)
128                 list.Add(1);
129             else
130                 list.Add(list[list.Count - 2] + list[list.Count - 1]);
131             if (number < 30)
132                 Recursion(number + 1, list);
133         }
134     }
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142 
143 
144 }