RosettaCodeData/Task/Longest-common-substring/C/longest-common-substring.c

43 lines
923 B
C

#include <stdio.h>
void lcs(const char * const sa, const char * const sb, char ** const beg, char ** const end) {
size_t apos, bpos;
ptrdiff_t len;
*beg = 0;
*end = 0;
len = 0;
for (apos = 0; sa[apos] != 0; ++apos) {
for (bpos = 0; sb[bpos] != 0; ++bpos) {
if (sa[apos] == sb[bpos]) {
len = 1;
while (sa[apos + len] != 0 && sb[bpos + len] != 0 && sa[apos + len] == sb[bpos + len]) {
len++;
}
}
if (len > *end - *beg) {
*beg = sa + apos;
*end = *beg + len;
len = 0;
}
}
}
}
int main() {
char *s1 = "thisisatest";
char *s2 = "testing123testing";
char *beg, *end, *it;
lcs(s1, s2, &beg, &end);
for (it = beg; it != end; it++) {
putchar(*it);
}
printf("\n");
return 0;
}