Dynamic Planning of common subsequence LCs

Returns the largest common subsequence of two sequences.

 

1. Recursion

 

/*

* Author: dengzhaoqun

* Date: 2011/04/28

*/

 

 

# Include <stdio. h>

# Include <stdlib. h>

# Include <string. h>

 

# Define length 1000

 

// Global variables

Char X [1000] = {'/0 '};

Char y [1000] = {'/0 '};

Int * c = NULL;

Char * B = NULL;

 

// Function declaration

Int * buildc (INT lenx, int leny );

Char * buildb (INT lenx, int leny );

Int lcrrecur (INT endx, int Endy, int leny );

Void trace (INT endx, int Endy, int leny );

Int main ()

{

Int lenx;

Int leny;

Int lcrn; // LCR number

 

// Get the input

Printf ("input sequence X :");

Scanf ("% s", & X [1]); // endx decrease from lenx to 1

X [0] = 'T'; // make the lenx not be 0

 

Printf ("input sequence y :");

Scanf ("% s", & Y [1]); // Endy decrease from leny to 1

Y [0] = 'F'; // make the leny not be 0

 

Lenx = strlen (x)-1;

Leny = strlen (y)-1;

 

// Built the C [] and B []

C = buildc (lenx, leny );

B = buildb (lenx, leny );

 

// Call the recurvise Function

Lcrn = lcrrecur (lenx, leny, leny); // endx, Endy, leny

 

// Output

Printf ("the LCR number is: % d/N", lcrn );

Printf ("the LCR :");

Trace (lenx, leny, leny );

Printf ("/N ");

 

// Release the memory

Free (C );

Free (B );

Return 0;

}

 

// --- Begin method buildc ---

Int * buildc (INT lenx, int leny)

{

Int * P = NULL;

Int I, J;

 

P = (int *) malloc (lenx + 1) * (leny + 1) * sizeof (INT ));

If (null = P)

{

Printf ("memory allocation failed./N ");

Exit (1 );

}

 

I = 0;

For (I; I <= lenx; I ++)

{

J = 0;

For (J; j <= leny; j ++)

{

P [I * (leny + 1) + J] =-1;

}

}

For (I = 0; I <= lenx; I ++)

P [I * (leny + 1)] = 0;

For (I = 0; I <= leny; I ++)

P [I] = 0;

 

Return P;

}

// --- End method buildc ---

 

// --- Begin method buildb ---

Char * buildb (INT lenx, int leny)

{

Char * Ch = NULL;

Int I, J;

 

Ch = (char *) malloc (lenx + 1) * (leny + 1) * sizeof (char ));

If (null = CH)

{

Printf ("memory allocation failed./N ");

Exit (1 );

}

 

I = 0;

For (I; I <= lenx; I ++)

{

J = 0;

For (J; j <= leny; j ++)

{

Ch [I * (leny + 1) + J] = 'E'; // indicate error

}

}

Return ch;

}

// --- End method buildb ---

 

// --- Begin method lcrrecur ---

Int lcrrecur (INT endx, int Endy, int leny)

{

Int tempx, Tempy;

 

Int * This = & (c [endx * (leny + 1) + Endy]);

If (* This! =-1)

Return (* This );

Else if (X [endx] = Y [Endy])

{

* This = lcrrecur (endx-1, endy-1, leny) + 1;

B [endx * (leny + 1) + Endy] = 'B'; // 'B' represents 'both'

}

Else

{

Tempx = lcrrecur (endx-1, Endy, leny );

Tempy = lcrrecur (endx, endy-1, leny );

If (tempx> Tempy)

{

* This = tempx;

B [endx * (leny + 1) + Endy] = 'X'; // decrease the endx

}

Else

{

* This = Tempy;

B [endx * (leny + 1) + Endy] = 'y'; // decrease the Endy

}

}

Return * this;

}

// --- End method lcrrecur ---

 

// --- Begin method Trace ---

Void trace (endx, Endy, leny)

{

Char * This = & (B [endx * (leny + 1) + Endy]);

If (endx = 0) | (Endy = 0 ))

Return;

If (* This = 'B ')

{

Trace (endx-1, endy-1, leny );

Printf ("% C", X [endx]);

}

Else if (* This = 'X ')

{

Trace (endx-1, Endy, leny );

}

Else if (* This = 'y ')

{

Trace (endx, endy-1, leny );

}

Else if (* This = 'E ')

{

Printf ("error./N ");

Exit (1 );

}

}

// --- End method Trace ---

2. Iterative Method

/*

* Author: dengzhaoqun

* Date: 2011/04/28

*/

 

 

# Include <stdio. h>

# Include <stdlib. h>

# Include <string. h>

 

# Define length 1000

 

// Global variables

Char X [1000] = {'/0 '};

Char y [1000] = {'/0 '};

Int * c = NULL;

Char * B = NULL;

 

// Function declaration

Int * buildc (INT lenx, int leny );

Char * buildb (INT lenx, int leny );

Void lcriterator (INT endx, int Endy, int leny );

Void trace (INT endx, int Endy, int leny );

Int main ()

{

Int lenx;

Int leny;

 

// Get the input

Printf ("input sequence X :");

Scanf ("% s", & X [1]); // endx decrease from lenx to 1

X [0] = 'T'; // make the lenx not be 0

 

Printf ("input sequence y :");

Scanf ("% s", & Y [1]); // Endy decrease from leny to 1

Y [0] = 'F'; // make the leny not be 0

 

Lenx = strlen (x)-1;

Leny = strlen (y)-1;

 

// Built the C [] and B []

C = buildc (lenx, leny );

B = buildb (lenx, leny );

 

// Call the recurvise Function

Lcriterator (lenx, leny, leny );

 

// Output

Printf ("the LCR number is: % d/N", C [(lenx + 1) * (leny + 1)-1]);

Printf ("the LCR :");

Trace (lenx, leny, leny );

Printf ("/N ");

 

// Release the memory

Free (C );

Free (B );

Return 0;

}

 

// --- Begin method buildc ---

Int * buildc (INT lenx, int leny)

{

Int * P = NULL;

Int I, J;

 

P = (int *) malloc (lenx + 1) * (leny + 1) * sizeof (INT ));

If (null = P)

{

Printf ("memory allocation failed./N ");

Exit (1 );

}

 

I = 0;

For (I; I <= lenx; I ++)

{

J = 0;

For (J; j <= leny; j ++)

{

P [I * (leny + 1) + J] =-1;

}

}

For (I = 0; I <= lenx; I ++)

P [I * (leny + 1)] = 0;

For (I = 0; I <= leny; I ++)

P [I] = 0;

 

Return P;

}

// --- End method buildc ---

 

// --- Begin method buildb ---

Char * buildb (INT lenx, int leny)

{

Char * Ch = NULL;

Int I, J;

 

Ch = (char *) malloc (lenx + 1) * (leny + 1) * sizeof (char ));

If (null = CH)

{

Printf ("memory allocation failed./N ");

Exit (1 );

}

 

I = 0;

For (I; I <= lenx; I ++)

{

J = 0;

For (J; j <= leny; j ++)

{

Ch [I * (leny + 1) + J] = 'E'; // indicate error

}

}

Return ch;

}

// --- End method buildb ---

 

// --- Begin method lcrrecur ---

Void lcriterator (INT endx, int Endy, int leny)

{

Int I, J;

Int tempx, Tempy;

Int * This = NULL;

For (I = 1; I <= endx; I ++)

For (j = 1; j <= Endy; j ++)

{

This = & (c [I * (leny + 1) + J]);

If (X [I] = Y [J])

{

* This = C [(I-1) * (leny + 1) + (J-1)] + 1;

B [I * (leny + 1) + J] = 'B'; // 'B' represent 'both'

}

Else

{

Tempx = C [(I-1) * (leny + 1) + J];

Tempy = C [I * (leny + 1) + (J-1)];

If (tempx> Tempy)

{

* This = tempx;

B [I * (leny + 1) + J] = 'X ';

}

Else

{

* This = Tempy;

B [I * (leny + 1) + J] = 'y ';

}

}

}

}

// --- End method lcrrecur ---

 

// --- Begin method Trace ---

Void trace (endx, Endy, leny)

{

Char * This = & (B [endx * (leny + 1) + Endy]);

If (endx = 0) | (Endy = 0 ))

Return;

If (* This = 'B ')

{

Trace (endx-1, endy-1, leny );

Printf ("% C", X [endx]);

}

Else if (* This = 'X ')

{

Trace (endx-1, Endy, leny );

}

Else if (* This = 'y ')

{

Trace (endx, endy-1, leny );

}

Else if (* This = 'E ')

{

Printf ("error./N ");

Exit (1 );

}

}

// --- End method Trace ---