This article summarizes common algorithm questions and answers for C# interviews. It has good learning and reference value. Share it for your reference. The details are as follows:
1. Write out the bubbles, select, and insert the sorting algorithm.
//Bubbling sort public class bubblesorter
{
public void sort(int[] list)
{
int i, j, temp;
bool done = false;
j = 1;
while ((j < ) && (!done))
{
done = true;
for (i = 0; i < - j; i++)
{
if (list[i] > list[i + 1])
{
done = false;
temp = list[i];
list[i] = list[i + 1];
list[i + 1] = temp;
}
}
j++;
}
}
}
//Select sort public class selectionsorter
{
private int min;
public void sort(int[] list)
{
for (int i = 0; i < - 1; i++)
{
min = i;
for (int j = i + 1; j < ; j++)
{
if (list[j] < list[min])
min = j;
}
int t = list[min];
list[min] = list[i];
list[i] = t;
}
}
}
//Insert sort public class insertionsorter
{
public void sort(int[] list)
{
for (int i = 1; i < ; i++)
{
int t = list[i];
int j = i;
while ((j > 0) && (list[j - 1] > t))
{
list[j] = list[j - 1];
--j;
}
list[j] = t;
}
}
}
2. There is a column of numbers 1, 1, 2, 3, 5,... Find the 30th number.
public class MainClass
{
public static void Main()
{
(Foo(30));
}
public static int Foo(int i)
{
if (i <= 0)
return 0;
else if (i > 0 && i <= 2)
return 1;
else return Foo(i - 1) + Foo(i - 2);
}
}
3. Programming: The cat screamed, all the mice began to escape, and the owner was awakened.
public delegate void SubEventHandler();
public abstract class Subject
{
public event SubEventHandler SubEvent;
protected void FireAway()
{
if ( != null)
();
}
}
public class Cat : Subject
{
public void Cry()
{
(cat cryed.);
();
}
}
public abstract class Observer
{
public Observer(Subject sub)
{
+= new SubEventHandler(Response);
}
public abstract void Response();
}
public class Mouse : Observer
{
private string name;
public Mouse(string name, Subject sub) : base(sub)
{
= name;
}
public override void Response()
{
(name + attempt to escape!);
}
}
public class Master : Observer
{
public Master(Subject sub) : base(sub){}
public override void Response()
{
(host waken);
}
}
class Class1
{
static void Main(string[] args)
{
Cat cat = new Cat();
Mouse mouse1 = new Mouse(mouse1, cat);
Mouse mouse2 = new Mouse(mouse2, cat);
Master master = new Master(cat);
();
}
}
4. There is a string "I am a good man", design a function, and returns "man good a am I".
static string Reverse()
{
string s = "I am a good man";
string[] arr = (' ');
string res = "";
for (int i = - 1; i >= 0; i--)
{
res += arr[i];
if (i > 0)
res += " ";
}
return res;
}
5. Five students, A, B, C, D, and E, may participate in the computer competition. According to the following conditions, who participated in the competition:
(1) When A participates, B also participates;
(2) Only one person from B and C participated;
(3) Both C and D participate, or do not participate;
(4) At least one of D and E participated;
(5) If A participates, then both A and D participate.
static void Main(string[] args)
{
char[] name={'A','B','C','D','E'};
int[] value = new int[5];
for (value[0]=0;value[0]<2;value [0]++)
for (value[1]=0; value[1] < 2; value[1]++)
for (value[2]=0; value[2] < 2; value[2]++)
for (value[3]=0; value[3] < 2; value[3]++)
for (value[4]=0; value[4] < 2; value[4]++)
{
if ((value[1] >= value[0]) && (value[1] + value[2] == 1) && (value[2] == value[3]) && (value[3] + value[4]==1) && (value[4]==0 || value[4]==1 && value[0]==1 && value[3]==1))
{
for (int i = 0; i < 5; i++)
{
if (value[i]==1)
{
("{0}join", name[i]);
}
else
{
("{0}不join", name[i]);
}
}
}
}
}
6. Question:
a user entered an integer value into a text box. Without using a buit-in library, convert the numeric string to its integer representation.
static int StringTolnt(string s)
{
int sum = 0;
for (int i = 0; i < ; i++)
sum = sum * 10 + (s[i] - '0');
return sum;
}
I believe that the description in this article has certain reference value for everyone's C# programming.