sysy-data/functional/sy/74_kmp.sy

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void get_next(int str[], int next[])
{
next[0] = -1;
int i = 0, j = -1;
while (str[i]) {
if (j == -1 || str[i] == str[j]) {
j = j + 1;
i = i + 1;
next[i] = j;
}
else
j = next[j];
}
}
int KMP(int dst[], int src[])
{
int next[4096];
get_next(dst, next);
int i = 0, j = 0;
while (src[j]) {
if (dst[i] == src[j]) {
i = i + 1;
j = j + 1;
if (!dst[i]) {
return j;
}
} else {
i = next[i];
if (i == -1) {
i = i + 1;
j = j + 1;
}
}
}
return -1;
}
int read_str(int buf[])
{
int i = 0;
while (1) {
buf[i] = getch();
if (buf[i] == 10)
break;
i = i + 1;
}
buf[i] = 0;
return i;
}
int main()
{
int dst[4096], src[4096];
read_str(dst);
read_str(src);
putint(KMP(dst, src));
putch(10);
return 0;
}