题目链接:http://poj.org/problem?id=3461
简单明了KMP，不过需要统计出现的次数。
在每次查询到一个的时候依旧要沿着失配边走而不是直接回到开头。
代码:
1 #include <cstdio>
2 #include <cstdlib>
3 #include <cmath>
4 #include <cstring>
5 #include <algorithm>
6 #include <string>
7 #include <queue>
8 #include <stack>
9 #include <map>
10 #include <set>
11 #include <vector>
12 #include <functional>
13 using namespace std;
14 #define inf 0x3f3f3f3f
15 #define maxn 2051
16
17
18
19 int getFail(char p[], int f[]){
20 f[0] = f[1] = 0;
21 int len = strlen(p);
22 for(int i = 1; i < len; i++){
23 int j = f[i];
24 while(j && p[i] != p[j]) j = f[j];
25 f[i + 1] = (p[i] == p[j]? j + 1: 0);
26 }
27 return 0;
28 }
29 int KMP(char t[], char p[], int f[]){
30 getFail(p, f);
31 int tlen = strlen(t), plen = strlen(p);
32 bool flag = false;
33 int rec = 0;
34 for(int i = 0, j = 0; i < tlen; i++){
35 while(j && p[j] != t[i])
36 j = f[j];
37 if(p[j] == t[i])
38 j++;
39 if(j == plen){
40 flag = true;
41 rec++; j = f[j];
42 continue;
43 }
44 }
45
46
47 return rec;
48 }
49 char t[1000005], p[10005];
50 int f[10005];
51 int main(){
52 int tp;
53 scanf("%d", &tp);
54 while(tp--){
55 scanf("%s %s", p, t);
56 memset(f, 0, sizeof(f));
57 int res = KMP(t, p, f);
58 printf("%d\n", res);
59 }
60 }
题目:
Oulipo
| Time Limit: 1000MS | Memory Limit: 65536K | |
| Total Submissions: 40186 | Accepted: 16146 |
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