Evaluate the implementation of the LCS algorithm (short implementation function) and the lcs Algorithm for the longest string of two strings in C language.

Evaluate the implementation of the LCS algorithm (short implementation function) and the lcs Algorithm for the longest string of two strings in C language.

/*************************************** * *********************************> File Name: lcs. c> Author: dingzhengsheng> Mail: dingzs3@asiainfo.com> Created Time: Wednesday, May 20, 2015> Version: v0.01> Description:> History: **************************************** * *******************************/# include <stdio. h> # include <time. h> # include <stdlib. h> # include <unistd. h> # include <string. h> # include <sys/time. h> # include <ctype. h> # include "test_time.h"
# Define DEBUG 1 void slow_bb (char * a, int lena, char * B, int lenb, char * c) {int I; int j; int index; int max = 0; int num = 0; int start; for (I = 0; I <lena; I ++) {for (j = 0; j <lenb; j ++) {int start1 = I; int start2 = j; while (start1 <lena-1) & (start2 <lenb-1) & (a [start1 ++] = B [start2 ++]) num ++; if (num> max) {max = num; start = I ;} num = 0 ;}} strncpy (c, a + start, max);} void lcs (char * a, int lena, char * B, int lenb, char * c) {int I; int j; int s [lena + 1]; memset (s, 0, sizeof (int) * (lena + 1); int maxlen = 0; int pos; # ifdef DEBUG int * dbg; dbg = (int *) malloc (sizeof (int) * (lenb + 1) * (lena + 1); memset (dbg, 0, sizeof (int) * (lenb + 1) * (lena + 1); # endif for (j = lenb-1; j> = 0; j --) {for (I = 0; I <lena; I ++) {if (B [j] = a [I]) {# ifdef DEBUG * (dbg + j * (lena + 1) + I) = s [I] = s [I + 1] + 1; # else s [I] = s [I + 1] + 1; # endif if (s [I]> maxlen) {maxlen = s [I]; pos = I ;}} else {/* if (s [I + 1]> maxlen) {maxlen = s [I + 1]; pos = I + 1 ;} */s [I] = 0 ;}}# ifdef DEBUG for (I = 0; I <lenb + 1; I ++) {if (I = 0) {printf (""); for (j = 0; j <lena; j ++) printf ("% c", a [j]); printf ("\ n");} if (I = lenb) printf (""); for (j = 0; j <lena + 1; j ++) {if (j = 0) printf ("% c", B [I]); printf ("% d", * (dbg + I * (lena + 1) + j);} printf ("\ n") ;}# endif strncpy (c, & a [pos], maxlen);} void main (int argc, char * argv []) {char * a; char * B; int a_len; int B _len; char * c; int n = 100; int I = 0; if (argc> = 1) n = atoi (argv [1]); if (argc> = 3) {a_len = atoi (argv [2]); B _len = atoi (argv [3]);} a = malloc (a_len); B = malloc (B _len); c = malloc (a_len); for (I = 0; I <a_len; I ++) a [I] = random () % 4 + 0x30; for (I = 0; I <B _len; I ++) B [I] = random () % 4 + 0x30; printf ("a = % s \ n", a); printf ("B = % s \ n ", b); memset (c, 0, sizeof (c); starts (); for (I = 0; I <n; I ++) slow_bb (a, a_len, b, B _len, c); ends (); printf ("slow_bb c = % s ts = % lld \ n", c, tt (); memset (c, 0, sizeof (c); starts (); for (I = 0; I <n; I ++) lcs (a, a_len, B, B _len, c ); ends (); printf ("slow_bb c = % s ts = % lld \ n", c, tt (); free (a); free (B ); free (c );}

Test_time.c:

#include<stdio.h>#include<time.h>#include <unistd.h>#include<string.h>#include<sys/time.h>#include<sys/resource.h>#include"test_time.h"#define SECTOUSEC 1000000static struct timeval tv1,tv2;void starts(){        gettimeofday(&tv1,NULL);}void ends(){        gettimeofday(&tv2,NULL);}long int get_diff_time(struct timeval *tv1, struct timeval *tv2){           long int n;              n = (tv2->tv_sec - tv1->tv_sec)*SECTOUSEC + tv2->tv_usec - tv1->tv_usec;                     return n;}long int tt(){        return get_diff_time(&tv1, &tv2);}

Test_time.h:

/*************************************** * *********************************> File Name: test_time.h> Author: dingzhengsheng> Mail: dingzs3@asiainfo.com> Created Time: Wednesday May 20, 2015 seconds> Version: v0.01> Description:> History: **************************************** * ******************************/# ifndef _ TEST_TIME_H # define _ TEST_TIME_Hvoid starts (); void ends (); long int tt (); # endif

　　

Running result: (the print of the matrix is controlled by macro DEBUG.) the latter takes longer because the print matrix

 

Note: The Code does not process multiple headers. The results of the two functions may be different. You can use arrays to record multiple headers of the same length.