C/C ++ algorithm learning notes-exchange method

Source: Internet
Author: User

Exchange method:

The procedures of the exchange method are the clearest and simplest. Each time, the current elements are compared and exchanged with the subsequent elements one by one.

[Cpp]
# Include <iostream. h>
 
Void ExchangeSort (int * pData, int Count)
 
{
 
Int iTemp;
 
For (int I = 0; I <Count-1; I ++)
 
{
 
For (int j = I + 1; j <Count; j ++)
 
{
 
If (pData [j] <pData [I])
 
{
 
ITemp = pData [I];
 
PData [I] = pData [j];
 
PData [j] = iTemp;
 
}
 
}
 
}
 
}
 

 
Void main ()
 
{
 
Int data [] = {10, 9, 8, 7, 6, 5, 4 };
 
ExchangeSort (data, 7 );
 
For (int I = 0; I <7; I ++)
 
Cout <data [I] <"";
 
Cout <"/n ";
 
}

# Include <iostream. h>

Void ExchangeSort (int * pData, int Count)

{

Int iTemp;

For (int I = 0; I <Count-1; I ++)

{

For (int j = I + 1; j <Count; j ++)

{

If (pData [j] <pData [I])

{

ITemp = pData [I];

PData [I] = pData [j];

PData [j] = iTemp;

}

}

}

}

 

Void main ()

{

Int data [] = {10, 9, 8, 7, 6, 5, 4 };

ExchangeSort (data, 7 );

For (int I = 0; I <7; I ++)

Cout <data [I] <"";

Cout <"/n ";

}


 

Before comparison | first time | second time | third time | fourth time | fifth time | sixth time

10 9 8 7 6 5 4

9 10 10 10 10 10 10

8 8 9 9 9 9 9

7 7 7 8 8 8 8

6 6 6 6 7 7 7

5 5 5 5 6 6

4 4 4 4 4 5

From the above algorithm, the efficiency is basically the same as that of the bubble method.

Reverse Order (worst case)

First round: 10, 9, 8, 7-> 9, 10, 8, 7-> 8, 10, 9-> 7, 10, 9, 8 (three exchanges)

Round 2: 7, 10, 9-> 7, 9, 10, 8-> 7, 8, 10, 9 (exchange twice)

First round: 7, 8, 10, 9-> 7, 8, 9, 10 (switching once)

Cycles: 6

Number of exchanges: 6

 

Others:

First round:,->, (exchange once)

Round 2: 7, 10, 8, 9-> 7, 8, 10, 9-> 7, 8, 10, 9 (exchange once)

First round: 7, 8, 10, 9-> 7, 8, 9, 10 (switching once)

Cycles: 6

Number of exchanges: 3

 

From the running table, the exchange is almost as bad as the bubble. This is true. The number of loops is also 1/2 * (n-1) * n, so the complexity of the algorithm is still O (n * n ). Because we cannot give all the information, we can only tell you that the exchange is equally bad (in some cases, slightly better, in some cases ).

 

Related Article

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.