sonyakc

import java.util.LinkedHashSet;
import java.util.Set;

public class Permutation {
  public static void main(String[] args) {
    String str = "sonya"; // 5 * 4 * 3 * 2 = 20 * 6 = 120
    Permutation permutation = new Permutation();
    StringBuilder builder = new StringBuilder();
    Set<String> permSet = new LinkedHashSet<>();
    permutation.permute(str, builder, permSet);