hdu1711(ac自动机思想)

#include <iostream>

#include <cstdio>

#include <cstring>

#include <string>

#include <algorithm>

using namespace std;

const int maxn = 1000010;

const int maxm = 10010;

//Accepted 1711 484MS 4260K 1569 B C++ Achiberx 

int a[maxn], b[maxn];

int n, m;

int next[maxm];



void getNext(){

    next[0] = 0;

    next[1] = 0;

    if(m<3) return;

    int j = 0;

    for(int i = 1; i < m; i++) {

        j = next[i];

        if(b[i]==b[j]) {

            next[i+1] = j+1;

            continue;

        }

        else {

            while(j>0) {

                j = next[j];

                if(b[i]==b[j]) {

                    next[i+1] = j+1;

                    break;

                }

            }

        }

    }

}



int match() {

    int j = 0;

    for(int i =0; i < n; i++) {

        while(j && a[i]!=b[j])  {

            j = next[j];

        }

        if(a[i]==b[j]) j++;

        if(j==m) {

            return i-m+2;

        }

    }

    return 0;

}



int main()

{

    int T;

    scanf("%d", &T);

    for(int v = 0; v < T; v++) {

        scanf("%d%d", &n, &m);

        for(int i = 0; i < n; i++) {

            scanf("%d", &a[i]);

        }

        for(int j = 0; j < m; j++) {

            scanf("%d", &b[j]);

        }

        getNext();

        int res = match();

        if(res) {

            printf("%d\n", res);

        }

        else{

            printf("-1\n");

        }

    }

    return 0;

}

/***********************

5

13 5

1 2 1 2 3 1 2 3 1 3 2 1 2

1 2 3 1 3

13 5

1 2 1 2 3 1 2 3 1 3 2 1 2

1 2 3 2 1

***********************/