学步园

数字kmp.

pure water.

#include <cstdio>
using namespace std;
const int MAXN = 1000005;
const int MAXM = 10005;
int n,m,a[MAXN],b[MAXM],k;
int next[MAXM];
void prekmp()
{
    next[0] = -1;
    int j = -1;
    for(int i=1;i<m;i++)
    {
        while(j!=-1 && b[j+1]!=b[i])    j = next[j];
        if(b[j+1]==b[i])    j++;
        next[i] = j;
    }
}

int kmp()
{
    int j = -1;
    for(int i=0;i<n;i++)
    {
        while(j!=-1 && b[j+1]!=a[i])    j = next[j];
        if(b[j+1]==a[i])    j++;
        if(j==m-1)  return i-j+1;
    }
    return -1;
}

int main()
{
    int T;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d %d",&n,&m);
        for(int i=0;i<n;i++)
            scanf("%d",a+i);
        for(int i=0;i<m;i++)
            scanf("%d",b+i);
        prekmp();
        printf("%d\n",kmp());
    }
}