What is the time complexity (Big-O) of the following code?

class Main { // Recursive function to generate all permutations of a String private static void permutations(String candidate, String remaining) { if (remaining.length() == 0) { System.out.println(candidate); }

for (int i = 0; i < remaining.length(); i++) { String newCandidate = candidate + remaining.charAt(i);

String newRemaining = remaining.substring(0, i) + remaining.substring(i + 1);

permutations(newCandidate, newRemaining); } }

// Find Permutations of a String in Java public static void main(String[] args) { String s = "ABC"; permutations("", s); } }