Time Limit:1000MS Memory Limit:65536KB 64bit IO Format:%I64d & %I64u
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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
在刚开始用ci.get()一个个的输入字符，然后竟然超时了，然后就直接将一行输入，就ac了，可见每次单独的IO操作都会耗费一定的时间，而且耗费的时间还不短。#include<iostream>using namespace std;char text[1000005];char w[10005];int nex[10005];void findNext(int n){ nex[0]=-1; int i=0; int k=-1; while(i<n) { if(-1==k || w[nex[i]]==w[i]) { i++; k++; nex[i]=k; } else { k=nex[k]; } }}int kmp(int n,int m){ int i=0; int j=0; int num=0; while(i<n) { if(text[i]==w[j]) { i++; j++; } else { j=nex[j]; } if(j==m) { j=nex[j]; num++; } if(-1==j) { j=0; i++; } } return num;}int main(){ int N; cin>>N; cin.get(); int n=0,m=0; while(N--) { n=0;m=0; cin>>w; m=strlen(w); cin>>text; n=strlen(text); findNext(m); int num=kmp(n,m); cout<<num<<endl; }
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