TaskL

#include <iostream>
#include <string>
#include <cstring>

using namespace std;

const int MAX_CHAR = 26;

void commonCharacters(string str[], int n)
{
    bool prim[MAX_CHAR];
    int k = 0;
    memset(prim, true, sizeof(prim));

    for (int i = 0; i < n; i++)
    {
        bool sec[MAX_CHAR] = { false };

        for (int j = 0; str[i][j]; j++)
            if (prim[str[i][j] - 'a'])
                sec[str[i][j] - 'a'] = true;
        memcpy(prim, sec, MAX_CHAR);
    }

    for (int i = 0; i < 26; i++)
        if (prim[i])
            cout << char(i + 'a') << " ";
        else
            k++;
    if (k == 26)
        cout << "NO COMMON CHARACTERS";
}

int main()
{
    int n;
    cin >> n;
    string* arr = new string[n];
    for (int i = 0; i < n; i++)
        cin >> arr[i];
    commonCharacters(arr, n);

}