http://acm.hdu.edu.cn/showproblem.php?pid=1711

Number Sequence

Time Limit: 10000/5000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 16080 Accepted Submission(s): 7100

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 Input

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

Sample Output

-1

Source

HDU 2007-Spring Programming Contest

Next里面存的是前缀和后缀的最大相似度

Next[i] 代表的是前 i 个数的最大匹配

#include<stdio.h>

#include<string.h>

#include<stdlib.h>

#define N 1000007

int M[N], S[N], Next[N];

void FindNext(int Slen)

{

    int i=, j=-;

    Next[] = -;

    while(i<Slen)

    {

        if(j==- || S[i]==S[j])

            Next[++i] = ++j;

        else

            j = Next[j];

    }

}

int KMP(int Mlen, int Slen)

{

    int i=, j=;

    FindNext(Slen);

    while(i<Mlen)

    {

        while(j==- || (M[i]==S[j] && i<Mlen && j<Slen))

            i++, j++;

        if(j==Slen)

            return i-Slen+;

        j = Next[j];

    }

    return -;

}

int main()

{

    int t;

    scanf("%d", &t);

    while(t--)

    {

        int n, m, i;

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

        for(i=; i<n; i++)

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

        for(i=; i<m; i++)

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

        printf("%d\n", KMP(n, m));

    }

    return ;

}

巴特西

（KMP 模板）Number Sequence -- Hdu -- 1711

Number Sequence

最新文章

热门文章