import java.util.*; // Program to solve puzzle by @Sweet Emotion. public class Program { static ArrayList p1 = new ArrayList(), p2 = new ArrayList(), p3 = new ArrayList(), p4 = new ArrayList(); public static void permutation(String str) { permutation("", str); } private static void permutation(String pre, String str) { int n = str.length(); if (n == 0) { boolean c1 = (pre.indexOf('G') < pre.indexOf('D')); boolean c2 = (pre.indexOf('I') < pre.indexOf('H')); boolean c3 = !((pre.indexOf('F') < 5) && (pre.indexOf('D') < 5)); boolean c4 = (pre.indexOf('B') < 5) ^ (pre.indexOf('G') < 5); boolean c5 = !((pre.indexOf('I') < 5) ^ (pre.indexOf('C') < 5)); boolean c6 = !(pre.indexOf('E') < 5); boolean c7 = (pre.indexOf('F') < pre.indexOf('I')); boolean condition = c1 && c2 && c3 && c4 && c5 && c6 && c7; boolean option1 = ((pre.indexOf('J') < 5) || (pre.indexOf('A') < 5)); boolean option2 = (pre.indexOf('D') < 5); boolean option3 = (pre.indexOf('B') < 5); boolean option4 = (pre.indexOf('F') < 5); if (condition && option1) p1.add(pre); if (condition && option2) p2.add(pre); if (condition && option3) p3.add(pre); if (condition && option4) p4.add(pre); } else { for (int i = 0; i < n; i++) permutation(pre + str.charAt(i), str.substring(0, i) + str.substring(i + 1, n)); } } public static void main(String[] args) { permutation("ABCDEFGHIJ"); System.out.println("Option 1 : " + p1.size() + " possibilities."); System.out.println("Option 2 : " + p2.size() + " possibilities."); System.out.println("Option 3 : " + p3.size() + " possibilities."); System.out.println("Option 4 : " + p4.size() + " possibilities."); } }

Challenge 3 (By Pixie)