| Time Limit: 1000MS | Memory Limit: 65536K | |
| Total Submissions: 37971 | Accepted: 15286 |
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
Source
1 #include<iostream>
2 #include<cstring>
3 #include<cstdio>
4 using namespace std;
5 int next[100010];
6 char p[10010],s[1000010];
7 int t,num,l1,l2;
8 void getnext(){
9 int j=0,k=-1;
10 next[0]=-1;
11 while(j<l2){
12 if(k==-1||p[j]==p[k]){ j++;k++;next[j]=k; }
13 else k=next[k];
14 }
15 }
16 int KMP(){
17 int num(0),i=0,j=0;
18 getnext();
19 while(i<l1){
20 if(j==-1||s[i]==p[j]){ i++;j++; }
21 else j=next[j];
22 if(j==l2) { num++;j=next[j]; }
23 }
24 return num;
25 }
26 int main()
27 {
28 scanf("%d",&t);
29 while(t--){
30 scanf("%s%s",p,s);
31 l1=strlen(s);l2=strlen(p);
32 printf("%d\n",KMP());
33 }
34 return 0;
35 }
注意这个题目的输入顺序，是先输入字串后母串，刚开始被坑了~
来源：https://www.cnblogs.com/suishiguang/p/6286006.html