HDOJ1686 Oulipo KMP

Oulipo

Time Limit: 3000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 2620    Accepted Submission(s): 1012


Problem Description
The French author Georges Perec (1936–1982) once wrote a book, La disparition, without the letter 'e'. He was a member of the Oulipo group. A quote from the book:

Tout avait Pair normal, mais tout s’affirmait faux. Tout avait Fair normal, d’abord, puis surgissait l’inhumain, l’affolant. Il aurait voulu savoir où s’articulait l’association qui l’unissait au roman : stir son tapis, assaillant à tout instant son imagination, l’intuition d’un tabou, la vision d’un mal obscur, d’un quoi vacant, d’un non-dit : la vision, l’avision d’un oubli commandant tout, où s’abolissait la raison : tout avait l’air normal mais…

Perec would probably have scored high (or rather, low) in the following contest. People are asked to write a perhaps even meaningful text on some subject with as few occurrences of a given “word” as possible. Our task is to provide the jury with a program that counts these occurrences, in order to obtain a ranking of the competitors. These competitors often write very long texts with nonsense meaning; a sequence of 500,000 consecutive 'T's is not unusual. And they never use spaces.

So we want to quickly find out how often a word, i.e., a given string, occurs in a text. More formally: given the alphabet {'A', 'B', 'C', …, 'Z'} and two finite strings over that alphabet, a word W and a text T, count the number of occurrences of W in T. All the consecutive characters of W must exactly match consecutive characters of T. Occurrences may overlap.

 
Input
The first line of the input file contains a single number: the number of test cases to follow. Each test case has the following format:

One line with the word W, a string over {'A', 'B', 'C', …, 'Z'}, with 1 ≤ |W| ≤ 10,000 (here |W| denotes the length of the string W).
One line with the text T, a string over {'A', 'B', 'C', …, 'Z'}, with |W| ≤ |T| ≤ 1,000,000.
 
Output
For every test case in the input file, the output should contain a single number, on a single line: the number of occurrences of the word W in the text T.

 
Sample Input
3 BAPC BAPC AZA AZAZAZA VERDI AVERDXIVYERDIAN
 
Sample Output
1 3 0
 
 1 /* 功能Function Description:     HDOJ-1686
 2     开发环境Environment:          DEV C++ 4.9.9.1
 3     技术特点Technique:
 4     版本Version:
 5     作者Author:                   可笑痴狂
 6     日期Date:                      20120814
 7     备注Notes:
 8          查找模式字串在主串中出现的次数(可以有部分重叠)-------KMP算法
 9  */
10  
11  #include<stdio.h>
12  #include<string.h>
13  
14  char s[1000005],t[10005];
15  int next[10005];
16  int k;
17  
18  void get_next(int len)
19  {
20      int i,j;
21      i=0;
22      j=-1;
23      next[0]=-1;
24      while(i<len)
25      {
26          if(j==-1||t[i]==t[j])
27          {
28              if(t[++i]==t[++j])
29                  next[i]=next[j];
30              else
31                  next[i]=j;
32          }
33          else
34              j=next[j];
35      }
36  }
37  
38  void KMP(int i,int len1,int len2)
39  {
40      int j=0;
41      while(i<len1)
42      {
43          if(j==-1||s[i]==t[j])   //继续比较后续字符
44          {
45              ++i;
46              ++j;
47          }
48          else                    //模式串向右移动
49              j=next[j];
50          if(j==len2)                 //匹配成功
51          {
52              ++k;
53              j=next[j];
54          }
55      }
56  }
57  
58  int main()
59  {
60      int len1,len2,n;
61      scanf("%d",&n);
62      while(n--)
63      {
64 
65          k=0;
66          scanf("%s",t);
67          scanf("%s",s);
68          len1=strlen(s);
69          len2=strlen(t);
70          get_next(len2);
71          KMP(0,len1,len2);
72          printf("%d\n",k);
73      }
74      return 0;
75  }
 
功不成,身已退
原文地址:https://www.cnblogs.com/dongsheng/p/2637525.html