Oulipo
Time Limit: 3000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 3770 Accepted Submission(s): 1485
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
kmp ....经典题
思路清晰,就不多说啦!...
就是求目标串在主串中出现几次,即匹配几次,,.
代码:
1 /*@coder 龚细军*/
2 #include<iostream>
3 #include<string>
4 #include<vector>
5 using namespace std;
6
7 int main()
8 {
9 int t,i,j;
10 string pw,ps;
11 cin>>t;
12 while(t--)
13 {
14 i=0,j=-1;
15 cin>>pw>>ps; /*pw作为目标串,ps作为主串*/
16 int lenpw=pw.length();
17 int lenps=ps.length();
18 vector<int>next(lenpw+1,0);
19 next[i]=-1;
20 while(i<lenpw)
21 {
22 if(j==-1||pw[i]==pw[j])
23 {
24 ++i;
25 ++j;
26 if(pw[i]!=pw[j])
27 next[i]=j;
28 else
29 next[i]=next[j];
30 }
31 else
32 j=next[j];
33 }
34 i=-1,j=-1;
35 int ans=0;
36 while(i<lenps)
37 {
38 if(j==-1||pw[j]==ps[i])
39 {
40 ++i;
41 ++j;
42 }
43 else
44 j=next[j];
45 if(j==lenpw)
46 ans++;
47 }
48 printf("%d\n",ans);
49 }
50 return 0;
51 }
View Code