HDU 1711 Number Sequence (简单KMP)

#include <stdio.h>
#include <string.h>

int next[10005];
int  str1[1000005],str2[10005];

void build_next(int len2)
{
	int i=0,j=-1;
	next[0] = -1;
	while (i < len2)
	{
		if (j==-1 || str2[i] == str2[j])
		{
			i++;
			j++;
			if (str2[i] != str2[j])
			{
				next[i] = j;
			}
			else
				next[i] = next[j];
		}
		else
			j = next[j];
	}
}

int KMP(int len1,int len2)
{
    build_next(len2);
	int i=0,j=0,cnt;
	
	while (i < len1)
	{
		if (j==-1 || str1[i] == str2[j])
		{
			i++;
			j++;
			if(j==len2)                 //在这里判断是否为全部匹配
				return i-len2+1;
		}
		else
			j = next[j];
	}
	return -1;                                 //最后还未匹配成功，直接返回-1
}

int main()
{
	int N,n,m,i;
	scanf("%d",&N);
	while (N--)
	{
		scanf("%d%d",&n,&m);
		for(i=0;i<n;i++)
			scanf("%d",&str1[i]);
        for(i=0;i<m;i++)
			scanf("%d",&str2[i]);
		if(n<m)
			printf("-1\n");
		else
		{
			n=KMP(n,m);
		   printf("%d\n",n);
		}
	}
	return 0;
}

。。。。。。。。。。。。。。。。。。。。。。。。。。。。。

分析：题目将字符串换成了数字，原理还是一样的，简单KMP  

Number Sequence

Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 13443    Accepted Submission(s): 6058

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