HDU 1711 Number Sequence（KMP）

Number Sequence

Time Limit : 10000/5000ms (Java/Other) Memory Limit : 32768/32768K (Java/Other)
Total Submission(s) : 27 Accepted Submission(s) : 13
Problem Description
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 Input213 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 1Sample Output6-1SourceHDU 2007-Spring Programming Contest

#include<iostream>#include<algorithm>#include<cstdio>#include<cstring>using namespace std;const int maxx=1e6+10;int Next[maxx];int s[maxx],p[maxx];int len1,len2;void getnext(){    int i=0,j=-1;    Next[0]=-1;    while(i<len1)    {        if(j==-1||p[i]==p[j])        {            ++i;            ++j;            if(p[i]==p[j])                Next[i]=Next[j];            else                Next[i]=j;        }        else            j=Next[j];    }}int getkmp(){    int num=0,i=0,j=0;    while(i<len2)    {        if(j==-1|s[i]==p[j])        {            ++i;++j;            if(j==len1)                return i-len1+1;        }        else            j=Next[j];    }    return -1;}int main(){    int t;    scanf("%d",&t);    while(t--)    {        scanf("%d%d",&len2,&len1);        for(int i=0;i<len2;i++)            scanf("%d",&s[i]);         for(int i=0;i<len1;i++)            scanf("%d",&p[i]);        getnext();        if(len2<len1)            printf("-1\n");        else            printf("%d\n",getkmp());    }    return 0;}