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 }
135
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142
143
144 }
