HDU1711 ——Number Sequence（KMP模板题）

 Given two sequences of numbers : a[1], a[2], ...... , a[N], and b[1], b[2], ...... , b[M] (1 <= M <= 10000, 1 <= N <= 1000000). Your task is to find a number K which make a[K] = b[1], a[K + 1] = b[2], ...... , a[K + M - 1] = b[M]. If there are more than one K exist, output the smallest one.

Input

The first line of input is a number T which indicate the number of cases. Each case contains three lines. The first line is two numbers N and M (1 <= M <= 10000, 1 <= N <= 1000000). The second line contains N integers which indicate a[1], a[2], ...... , a[N]. The third line contains M integers which indicate b[1], b[2], ...... , b[M]. All integers are in the range of [-1000000, 1000000].

Output

For each test case, you should output one line which only contain K described above. If no such K exists, output -1 instead.

Sample Input

213 51 2 1 2 3 1 2 3 1 3 2 1 21 2 3 1 313 51 2 1 2 3 1 2 3 1 3 2 1 21 2 3 2 1

Sample Output

6-1

代码：

#include <iostream>#include <cstdio>using namespace std;int next1[10005];int board[10005];int str[1000005];int N,M;void getNext(){    int k = -1;    int j = 0;    next1[0] = -1;//next数组最好是从0开始要不然会很麻烦     while(j<M){        if(k == -1 || board[j] == board[k]){            if(board[j+1] == board[k+1]){                 next1[++j] = next1[++k];            }            else next1[++j] = ++k;        }        else {            k = next1[k];        }    }}int Find(){//返回匹配到的位置     getNext();    int temp1 = 0,temp2 = 0;    while(temp1<N && temp2<M){        if(temp2 == -1 || str[temp1] == board[temp2]){            temp1++;temp2++;        }        else{            temp2 = next1[temp2];        }    }     if(temp2 == M)return temp1-temp2;    else return -1;  }int main(){    int T;    cin>>T;    while(T--){        scanf("%d %d",&N,&M);        for(int i=0 ; i<N ; i++)scanf("%d",&str[i]);         for(int i=0 ; i<M ; i++)scanf("%d",&board[i]);//这里和next数组统一也从0开始         int re = Find();        if(re == -1)printf("-1\n");        else printf("%d\n",re+1);//由于前面是从0开始而题中是从1开始所以这里加1     }    return 0;}