sample input output work fine. but it still get WA. can anyone give me a hint? how can i handel the equal part

#include <iostream>
#include <string>
#include <sstream>
using namespace std;

void display(string *s)
{
    int i = 0;
    while (s[i] != "\0")
    {
        cout << s[i];
        i++;
    }
    cout << endl;
}
main()
{
    int n;
    string t1, t2;
    getline(cin, t1);a
    stringstream ss;
    string s[51];
    ss << t1;
    ss >> n;
    ss.clear();
    while (n--)
    {
        getline(cin, t1);
        ss << t1;
        int i = 0;
        while (ss >> t2)
        {
            s[i] = t2 + " ";
            i++;
        }
        s[i] = "\0";
        int idx;
        for (i = 0; s[i] != "\0"; i++)
        {
            idx = i;
            for (int j = i + 1; s[j] != "\0"; j++)
            {
                if (s[idx].length() < s[j].length())
                {
                    idx = j;
                }
            }
            if (idx != i)
            {
                swap(s[i], s[idx]);
            }
        }
        s[i - 1].pop_back();
        display(s);
        ss.clear();
    }
}