考研编程练习---StringMatching(后缀表达式)-优快云博客

本文深入探讨了文本编辑程序中常见的字符串匹配问题，包括如何在文本中查找特定模式，以及算法的具体实现步骤。通过实例分析，详细阐述了模式匹配的原理与应用。

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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：

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;
}

转载于:https://www.cnblogs.com/Alex0111/p/4655548.html