楼主，基于字典树的第21行会出现越界问题，比如case：

zyyhappy

zyy

不同长度的解决方案，用标识isEnd来控制，贴一下我的代码，如果有问题，还望各位指正。

#include <iostream>
#include <list>
#include <vector>
#include <map>
#include <string>
#include <algorithm>
using namespace std;

class Tire
{
public:
    Tire *next[26];
    bool isEnd;
    Tire()
    {
        for(int i = 0 ; i < 26 ;i++)
            next[i] = nullptr;
        isEnd = false;
    }
};


bool findSS(Tire *root, string s)
{
    for(int i=0 ; i < s.size() ;i++)
    {
        int index = s[i] - 'a';
        if(root->next[index] == nullptr)
            return false;
        root = root->next[index];
    }
    return root->isEnd;
}

void addTire(Tire* node, string word)
{
    for(int i = 0 ; i < word.size() ;i++)
    {
        int index = word[i] - 'a';
        if(node->next[index] == nullptr)
            node->next[index] = new Tire();
        node = node->next[index];
    }
    node->isEnd = true;
}

int main()
{
    int t,n;
    string s;
    cin >> t;
    while(t--)
    {
        cin >> n;
        Tire *root = new Tire();
        vector<string> v;
        bool sign = false;
        for(int i = 0 ; i < n ; i++)
        {
            cin >> s;

            string new_s = s+s;
            for(int k = 0 ; k < s.size()+1 ;k++)
            {
                string find_s = new_s.substr(k,s.size());
                if(findSS(root,find_s))
                {
                    sign = true;
                    break;
                }
                reverse(find_***egin(), find_s.end());
                if(findSS(root, find_s))
                {
                    sign = true;
                    break;
                }
            }
            addTire(root, s);


        }
        if(sign) cout << "Yeah" << endl;
        else cout << "Sad" << endl;

    }
}