C # Recursive Algorithms

The first question I encountered was: Calculate the Array {, 5, 8 .......} the 30th-bit value does not require recursion. I wrote the following code:

 

Static void Main (string [] args)
...{

Int [] num = new int [30];
Num [0] = 1;
Num [1] = 1;
Int first = num [0];
Int second = num [1];
For (int I = 2; I <num. Length; I ++)
...{
Num [I] = first + second;
First = second;
Second = num [I];
}
Console. WriteLine (num [29]);
Console. ReadLine ();

}

It is very cumbersome to write, so it is easy to understand and understand. The following code is used:

 

Static void Main (string [] args)
...{

Console. WriteLine (Process1 (30 ));
Console. ReadLine ();
}
Public static int Process1 (int I)
...{

 

// Calculate the {30th, 5, 8 ......} bits of the array.
If (I = 0) return 0;
If (I = 1) return 1;
Else
Return Process1 (I-1) + Process1 (I-2 );
}
I have done some exercises:

1. Calculate the value of 1 + 2 + 3 + 4 +... + 100

 

Static void Main (string [] args)
...{
Console. WriteLine (Process2 (100 ));
Console. ReadLine ();
}
Public static int Process2 (int I)
...{
// Calculates the value of 1 + 2 + 3 + 4 +... + 100
If (I = 0) return 0;
Return Process2 (I-1) + I;

}
2. Calculate the value of 1-2 + 3 +-4 + 5-6 + 7-8 + 9

 

Static void Main (string [] args)
...{

Console. WriteLine (Process3 (9)-Process3 (8 ));
Console. ReadLine ();
}

Public static int Process3 (int I)
...{
// Calculate the value of 1-2 + 3 +-4 + 5-6 + 7-8 + 9
If (I = 0) return 1;
If (I = 1) return 2;
Else return Process3 (I-2) + I;
}
3. Tower of Hanoi Problems

 

Static void Main (string [] args)
...{
Hanoi (5, 'A', 'B', 'C ');
Console. ReadLine ();
}
Public static void Hanoi (int n, char A, char B, char C)
...{
// Tower of Hanoi Problems
// Move n plates from seat a with seat B to seat C
If (n = 1) Move (A, C );
Else
...{
Hanoi (n-1, A, C, B );
Move (A, C );
Hanoi (n-1, B, A, C );
}

}
Public static void Move (char startPlace, char endPlace)
...{
Console. WriteLine ("Move {0} To {1}", startPlace, endPlace );
}
4. Use recursion to convert an integer n into a string. For example, if you input 483, the number of digits of the output string "483". n is uncertain. It can be an integer of any digits.

 

Static void Main (string [] args)
...{
IntToString (483 ,"");
Console. ReadLine ();
}
Public static void IntToString (int input, String output)
...{
// Use recursion to convert an integer n into a string. For example, if you input 483, the number of digits of the output string "483". n is uncertain. It can be an integer of any digits.
// String output = "";
Output = input % 10 + output;
If (input/10! = 0)
...{
IntToString (input/10, output );
}
Else Console. WriteLine (output );
}

This article from the CSDN blog, reproduced please indicate the source: http://blog.csdn.net/inkstone2006/archive/2008/01/22/2057853.aspx