Oulipo
Time Limit : 3000/1000ms (Java/Other) Memory Limit : 32768/32768K (Java/Other)
Total Submission(s) : 98 Accepted Submission(s) : 63
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
Source
华东区大学生程序设计邀请赛_热身赛
题目意思很明显了就是kmp 求第一个串在第二个里面出现几次 假如说主串是 a b a b a b c d a b a b a b h f a b a b a b 子串是 ababab
i 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
a b a b a b c d a b a b a b h f a b a b a b
a b a b a b
j -1 0 0 1 2 3 4
这是子串的跳转表
i 0 1 2 3 4 5 6
a b a b a b
j -1 0 0 1 2 3 4
点击这里 kmp详解
#include<cstdio> #include<cstring> const int M=10000+10; char str2[M*100],str1[M]; int p[M]; int cnt,len1,len2; void getp() { int i=0,j=-1; p[i]=j; while(i<len1) { if(j==-1||str1[i]==str1[j]) { i++;j++; p[i]=j; } else j=p[j]; } } void kmp() { getp(); int i=0,j=0; while(i<len2) { if(j==-1||str2[i]==str1[j]) { i++;j++; if(j==len1) cnt++; // 每次查到匹配串长度是就说明出现了一个匹配串 } else j=p[j]; } } int main() { int T; scanf("%d",&T); while(T--) { scanf("%s%s",str1,str2); len1=strlen(str1); len2=strlen(str2); cnt=0; kmp(); printf("%d\n",cnt); } return 0; }