/* Challenge: Next Largest Permutation Given an integer, find the next largest integer using ONLY the digits from the given integer. Example: 123 ➡132 135 ➡153 https://code.sololearn.com/ctHABk6K12tq/?ref=app */ import java.util.*; public class NextLargestInteger { static Scanner sc = new Scanner(System.in); static int [] permutations; static ArrayList digits; public static void main(String[] args) { try{ int num = sc.nextInt(); System.out.println("You entered "+num); permutations = new int[permute(num)-1]; for(int i=0;i select = new ArrayList<>(); for(int i:permutations){ if(i>num) select.add(i); } if(select.size()==0){ nextLargest = num; } else nextLargest = Collections.min(select); System.out.println("Next largest integer is "+nextLargest); } catch(InputMismatchException e){ System.out.println("Invalid input"); } finally { sc.close(); } } static int factorial(int num){ if(num==0|num==1) return 1; else return num * factorial(num-1); } static int permute(int num){ int result; digits = new ArrayList<>(); for(int i=num;i>0;i/=10){ digits.add(i%10); } result = factorial(digits.size()); ArrayList uniqueInt = getUnique(digits); for(int i:uniqueInt){ result/=factorial(numOccurence(i)); } return result; } static int numOccurence(int num){ int occurence = 0; for(int i:digits){ if(i==num) occurence++; } return occurence; } static ArrayList getUnique(ArrayList a){ ArrayList unique = new ArrayList<>(); for(int i:a){ if(!(inList(i,unique))) unique.add(i); } return unique; } static boolean inArray(int num){ for(int x:permutations){ if(x==num) return true; } return false; } static boolean inList(int x,ArrayList a){ for(int i:a){ if(i==x) return true; } return false; } }

Next Largest Permutation Challenge