POJ3461 KMP快速字符串匹配

#include<stdio.h>#include<stdlib.h>#include<string.h>#include<iostream>#include<algorithm>using namespace std;const int dmax=1000100;char s[dmax],p[dmax];int next[dmax];void get_next(char *p){int k=-1,j=0,n=strlen(p);next[0]=-1;while (j<n){if (k==-1 || p[k]==p[j]){k++;j++;if (p[j]!=p[k])next[j]=k;else next[j]=next[k];}else k=next[k];}}int kmp(char *s,char *p){int i=0,j=0,x=strlen(s),y=strlen(p),ans=0;get_next(p);while (i<x){if (j==y){ans++;j=next[j];}if (j==-1 || s[i]==p[j]){i++;j++;}else j=next[j];}if (j==y)ans++;return ans;}int main(){int T;scanf("%d",&T);getchar();while (T--){memset(p,0,sizeof(p));memset(s,0,sizeof(s));memset(next,0,sizeof(next));gets(p);gets(s);printf("%d\n",kmp(s,p));}return 0;}