串应用- 计算一个串的最长的真前后缀

#include<iostream>
#include<string>
#include<algorithm>
using namespace std;
string matched_Prefix_Postfix(string s)
{
    int slength=s.size();
    string before[slength-1];
    string after[slength-1];
    for(int i=0;i<slength-1;i++)
    {
        before[i]=s.substr(0,i);
    }
    reverse(s.begin(),s.end());
    for(int i=0;i<slength-1;i++)
    {
        after[i]=s.substr(0,i);
        reverse(after[i].begin(),after[i].end());
    }
    reverse(s.begin(),s.end());
    int Max=0;
    int index=-1;
    for(int i=0;i<slength-1;i++)
    {
        for(int j=0;j<slength-1;j++)
        {
            if(before[i]==after[j])
            {
                int t=after[i].size();
                if(t>Max)
                {
                    index=i;
                    Max=t;
                }
            }
        }
    }
    if(Max==0)
    {
        string e="empty";
        return e;
    }
    else
    {
        string f=before[index];
        return f;
    }
}
 
int main()
{
    int T;
    cin>>T;
    while(T--)
    {
        string s;
        cin>>s;
        cout<<matched_Prefix_Postfix(s)<<endl;
    }
    return 0;
}