poj 3461

#include<stdio.h>

#include<string.h>

char s[11000],t[1100000];

int next[11000];

void getkmp(int len) {

    int j,k;

    next[0]=-1;

    j=0;k=-1;

    while(j<len) {

        if(k==-1||s[k]==s[j]) {

            j++;k++;

            if(s[j]!=s[k])

                next[j]=k;

            else

                next[j]=next[k];

        }

        else

            k=next[k];

    }

    return ;//关键点是他会把next[len]的值求出来即为本字符串中的相同数即k的值

}

int kmp(int lens,int lent) {

    int i,j,k=0;

    i=j=0;

    while(i<lent) {

        if(t[i]==s[j]) {

            i++;j++;

         

        }

        else {

            if(next[j]!=-1)//当j==lens时肯定会执行这一步开始比较第k+1个

                j=next[j];

            else {

                j=0;i++;

            } 

        }    

        if(j==lens)//++

            k++;

     

    }

    return k;

}

int main() {

    int tt,lens,lent,i;

    scanf("%d",&tt);

    while(tt--) {

        scanf("%s",s);

        scanf("%s",t);

        lens=strlen(s);

        lent=strlen(t);

        getkmp(lens);

        printf("%d\n",kmp(lens,lent));

    }

    return 0;

}

转载于:https://www.cnblogs.com/thefirstfeeling/p/4410821.html