How to compare the tag of HTML files in C++?

Question

 

      I want to compare several HTML files which contains many string tags so I am looking for the best ways which have less time complexity .

For Example:

There are 2 HTML files below which contain many tags which are string so I want to compare them and count the similar tags at last by using these formulas:

 

1. Average of similar tags of each two HTML files = (Quantity of same tags in first file) + (Quantity of same tags in second file) / (Sum of all second column of first file) + (Sum of all second column of second file).

 

2. Main Function for calculating: F ( File1,File2 ) = ((Quantity of tags which are same in both files) / ( Quantity of all tags of first and second files - Quantity of tags which are same in both files ) ) * (Average of similar tags of each two HTML files)

 

counter: which has the quantity of similar tags of two HTML files.

Note: The second columns contain the quantity of each tag in current HTML file.

 

The first HTML file:

 

joiuh	12
@62jj	10
k6235	2
99ui*	3
00Qyu67	9
*8455	7

Sum of all second column = 43

 

The Second HTML File :

 

00Qyu67	20
NY%%%20	1
UWCN10	13
89PO*	6
$$CS40	11
@62jj	56
k6235	10

Sum of all second column = 117

 

In this example:

 

Average of similar tags of each two HTML files: ( ( 10 + 9 + 2 ) + ( 56 + 20 + 10 ) ) / ( ( 43 ) + ( 117 ) ) = 107 / 160 = 0.66

 

F ( File1,File2 ) = ( ( 3 ) / ( 13 - 3 ) ) * 0.66 = 0.198