HDU5918-Sequence I（KMP）

Sequence I

                                                                          Time Limit: 3000/1500 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)
                                                                                                        Total Submission(s): 444    Accepted Submission(s): 168

Problem Description

Mr. Frog has two sequences  a1,a2,⋯,an and  b1,b2,⋯,bm and a number p. He wants to know the number of positions q such that sequence  b1,b2,⋯,bm is exactly the sequence  aq,aq+p,aq+2p,⋯,aq+(m−1)p where  q+(m−1)p≤n and  q≥1.

 

Input

The first line contains only one integer  T≤100, which indicates the number of test cases.

Each test case contains three lines.

The first line contains three space-separated integers  1≤n≤106,1≤m≤106 and  1≤p≤106.

The second line contains n integers  a1,a2,⋯,an(1≤ai≤109).

the third line contains m integers  b1,b2,⋯,bm(1≤bi≤109).

 

Output

For each test case, output one line “Case #x: y”, where x is the case number (starting from 1) and y is the number of valid q’s.

 

Sample Input

2 6 3 1 1 2 3 1 2 3 1 2 3 6 3 2 1 3 2 2 3 1 1 2 3

 

Sample Output

Case #1: 2 Case #2: 1

 

Source

2016中国大学生程序设计竞赛（长春）-重现赛

题意：给定序列a、序列b和整数p，求有多少个k使得b1、b2、b3……bm恰好是ak、ak+p、ak+2p、……ak+（m-1）p

解题思路：KMP变形

#include 
#include 
#include 
#include 
#include 

using namespace std;

int a[1000900],b[1000090];
int nt[1000090],n,m,p,sum;

void get_next()
{
    nt[0]=-1;
    for(int i=0; i=0&&b[i]!=b[k])
            k=nt[k];
        nt[i+1]=k+1;
    }
}

void kmp(int x)
{
    int i=x,j=0;
    while(i=m) sum++,j=nt[j];
    }
}

int main()
{
    int t,cas=0;
    scanf("%d",&t);
    while(t--)
    {
        sum=0;
        scanf("%d %d %d",&n,&m,&p);
        for(int i=0; in)
        {
            printf("Case #%d: 0\n",++cas);
            continue;
        }
        get_next();
        for(int i=0; i