HDU 2203 kmp

很有意思的一道题，一看感觉无从下手，后来一想，其实把匹配串复制一遍，然后用KMP搜一遍就行了、

#include<stdio.h>#include<string.h>#include<cstring>#define val 100005int lens,lenp,next[val];char s[val*2],p[val];bool kmp();int main(){while(scanf("%s",s)!=EOF){scanf("%s",&p);lens=strlen(s);lenp=strlen(p);strncpy(s+lens,s,lens);lens*=2;if(kmp()) printf("yes\n");else printf("no\n");}return 0;}bool kmp(){void set_next();int i,j;i=j=0;set_next();while(i<lens&&j<lenp){if(j==-1||s[i]==p[j]){i++;j++;}else j=next[j];}if(j<lenp) return false;else return true;}void set_next(){int j,k;j=0,k=-1;next[j]=k;while(j<lenp){if(k==-1||p[j]==p[k]){k++;j++;next[j]=k;}else k=next[k];}}