AC日记——Number Sequence hdu 1711

Number Sequence

Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 24928    Accepted Submission(s): 10551

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

2 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

6 -1

 

 

Source

HDU 2007-Spring Programming Contest 

 

 

思路：

　　kmp模板；

 

 

来，上代码：

#include<iostream>
#include<cstring>
#include<cstdlib>
#include<cstdio>
using namespace std;

const int N = 1000002;
int nest[1000002],n,m;
int s[1000002],t[1000002];
int slen,tlen;

void getnest()
{
    memset(nest,0,sizeof(nest));
    int j,k;
    j=0;k=-1;nest[0]=-1;
    while(j<tlen)
    {
        if(k==-1||t[j]==t[k])
            nest[++j]=++k;
        else k=nest[k];
    }
}

int kmp_index()
{
    int i=0;int j=0;
    getnest();
    while(i<slen&&j<tlen)
    {
        if(j==-1||s[i]==t[j])
        {
            i++;j++;
        }
        else j=nest[j];
    }
    if(j==tlen) return i-tlen+1;
    else return -1;
}

int kmp_count()
{
    int ans=0;
    int i,j=0;
    if(slen==1&&tlen==1)
    {
        if(s[0]==t[0]) return 1;
        else return 0;
    }
    getnest();
    for(i=0;i<slen;i++)
    {
        while(j>0&&s[i]!=t[j])
        {
            j=nest[j];
        }
        if(s[i]==t[j]) j++;
        if(j==tlen)
        {
            ans++;
            j=nest[j];
        }
    }
    return ans;
}

int main()
{
    int TT;
    int i,cc;
    cin>>TT;
    while(TT--)
    {
        cin>>n>>m;
        for(int i=0;i<n;i++)
            cin>>s[i];
        for(int j=0;j<m;j++)
            cin>>t[j];
        tlen=m,slen=n;
        cout<<kmp_index()<<endl;
    }
    return 0;
}