【HDU 1686 Oulipo】
Time Limit: 3000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 16166 Accepted Submission(s): 6444
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
Recommend
lcy
题解：
①KMP算法,统计匹配个数。
#include<stdio.h>
#include<cstring>
#define go(i,a,b) for(int i=a;i<=b;i++)
const int N=1000003;
int C,n,m,f[N],j,ans;char P[N],T[N];
int main()
{
scanf("%d",&C);
while(ans=0,C--&&scanf("%s%s",P,T))
{
m=strlen(P);
n=strlen(T);
f[0]=f[1]=0;
go(i,1,m-1){j=f[i];while(j&&P[j]!=P[i])j=f[j];f[i+1]=P[i]==P[j]?j+1:0;}j=0;
go(i,0,n-1){while(j&&P[j]!=T[i])j=f[j];ans+=(j+=P[j]==T[i])==m;}
printf("%d\n",ans);
}
return 0;
}//Paul_Guderian
我曾经追寻的一切,现在都没有找到,
你知道我一直要的,不是这个角落…… ————汪峰《彼岸》
