- 题目描述：
-
Finding all occurrences of a pattern in a text is a problem that arises frequently in text-editing programs.
Typically,the text is a document being edited,and the pattern searched for is a particular word supplied by the user.
We assume that the text is an array T[1..n] of length n and that the pattern is an array P[1..m] of length m<=n.We further assume that the elements of P and T are all alphabets(∑={a,b...,z}).The character arrays P and T are often called strings of characters.
We say that pattern P occurs with shift s in the text T if 0<=s<=n and T[s+1..s+m] = P[1..m](that is if T[s+j]=P[j],for 1<=j<=m).
If P occurs with shift s in T,then we call s a valid shift;otherwise,we calls a invalid shift.
Your task is to calculate the number of vald shifts for the given text T and p attern P.
- 输入：
-
For each case, there are two strings T and P on a line,separated by a single space.You may assume both the length of T and P will not exceed 10^6.
- 输出：
-
You should output a number on a separate line,which indicates the number of valid shifts for the given text T and pattern P.
- 样例输入：
-
abababab abab
- 样例输出：
-
3
- 经典代码：
- #include <iostream>
#include <string>
using namespace std;
string t,p;
string s;
int main(int argc,char* argv[]){
while(cin>>t>>p){
int c = 0;
for(int i=0;i<t.length()-p.length()+1;i++){
s = t.substr(i,p.length());
if(p==s){
c++;
}
}
cout<<c<<endl;
}
return 0;
}