Merkkijono

input/code.cpp: In function 'int main()':
input/code.cpp:11:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j = 0; j <= s.length(); j+=2) {
                  ~~^~~~~~~~~~~~~

#include <iostream>
#include <stdio.h>
#include <math.h>

int main ()
{
	int n; std::cin >> n;
	const std::string alphabet[16] = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p"};
	std::string s = "a";
	for(int i = 1; i < n; i++) {
		for(int j = 0; j <= s.length(); j+=2) {
			s = s.insert(j, alphabet[i]);
		}
	}
	std::cout << s;
}

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