soal02.js

function recur(digits, i, n, str) {

	if (i == n && typeof(str) != 'undefined') {
		//console.log(str)
		return;
	}
	
	var alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
	var sum = 0;

	for (j = i; j <= Math.min(i + 1, n - 1); j++) {
        console.log(j)
        sum = (sum * 10) + digits[j];
		if (sum <= 26)
			recur(digits, j + 1, n, str + alphabet[sum - 1]);
	}
}

var digits = [1,1,2,3];
	
var n = digits.length;
	
var str;

recur(digits, 0, n, str);