Merkkijono

input/code.cpp: In function 'int main()':
input/code.cpp:10:32: warning: suggest parentheses around '-' inside '<<' [-Wparentheses]
     int c = (int) 1 << (n + 1) - 1;
                        ~~~~~~~~^~~

#include <cmath>
#include <iostream>

using namespace std;

int main()
{
    int n;
    cin >> n;
    int c = (int) 1 << (n + 1) - 1;
    char base = 'a' + n - 1;

    for(int i = 0; i < c; i++) {
        for(int j = 0; j < n; j++) {
            //cout << i << " " << (1 << (j + 1)) << " " << ((1 << j) - 1) << endl;
            if(i % (1 << (j + 1)) == (1 << j) - 1) {
                cout << (char) (base - j);
                break;
            }
        }
    }

    cout << "\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED