/**
* Doesn't work with string containing null bytes
*/
bool isSubstring(const std::string& haystack, const std::string& needle) {
auto pi = prefixFunction(needle + '\0' + haystack);
for (auto value: pi) {
if (value == needle.size()) {
return true;
}
}
return false;
}
int KMP(string s,string p) {
int ret=0,j=0,ln=s.size();;
prefixFunction(p);
for(int i=0; i<ln; i++) {
while(j && s[i]!=p[j]) j=pre[j-1];
if(s[i]==p[j]) j++;
if(j==(int)p.size()) ret++;
}
return ret;
}
