hdu 1711 Number Sequence

思路：裸裸的kmp算法；

#include<stdio.h>#include<string.h>int next[5000100],a[5000100],b[5000010];int n,m;void getnext(){    int i=0,j=-1;    memset(next,0,sizeof(next));    next[0]=-1;    while(i<m)    {        if(j==-1||b[i]==b[j]) next[++i]=++j;        else j=next[j];    }}int kmp(){    int i,j=0;    for(i=0;i<n;)    {        if(a[i]==b[j])        {            if(j==m-1) return i-(m-1)+1;            i++,j++;        }        else        {             j=next[j];             if(j==-1) {i++;j=0;}        }    }    return -1;}int main(){   int T,i,j,k;   scanf("%d",&T);   while(T--)   {       scanf("%d%d",&n,&m);       for(i=0;i<n;i++) scanf("%d",&a[i]);       for(i=0;i<m;i++) scanf("%d",&b[i]);       if(n<m)       {         printf("-1\n");         continue;       }       getnext();       printf("%d\n",kmp());   }   return 0;}