Problem B Oulipo(KMP基础)

题目大意：

　　给你一个模式串和一个文本串，问你模式串在文本串中出现的次数，可能出现重叠的情况。

代码：

# include<cstdio>
# include<iostream>
# include<cstring>

using namespace std;

char s2[10004];
char s1[1000004];
int nxt[10004];

void get_next()
{
    int t1 = 0,t2;
    t2 = nxt[0] = -1;
    int len = strlen(s2);
    while ( t1<len )
    {
        if ( t2==-1||s2[t2]==s2[t1] )
        {
            t1++;t2++;
            nxt[t1] = t2;
        }
        else
            t2 = nxt[t2];
    }
}

int kmp ( char *s1, char *s2 )
{
    int len1 = strlen(s1), len2 = strlen(s2);
    int t1 = 0,t2 = 0;
    int times = 0;
    while ( t1 < len1 )
    {
        if ( t2==-1||s1[t1]==s2[t2] )
        {
            t1++;t2++;
        }
        else
            t2 = nxt[t2];
        if ( t2==len2 )
        {
            times+=1;
            t2 = nxt[t2];
        }
    }
    return times;
}


int main(void)
{
    int t;scanf("%d",&t);
    while ( t-- )
    {
        scanf("%s%s",s2,s1);
        get_next();
        int ans = kmp(s1,s2);
        printf("%d
",ans);
    }


    return 0;
}