RecursionAndBacktracking/Subsequences.java at main · adv11/RecursionAndBacktracking · GitHub

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packageRecursionAndBacktracking;

importjava.util.ArrayList;
importjava.util.Scanner;

publicclassSubsequences {
publicstaticvoidprintSubsequences(intindex, int[] array, intsize, ArrayList<Integer> subsequences){
if(index == size){
for(intele : subsequences){
System.out.print(ele + " ");
 }

if(subsequences.size() == 0){ // condition for null set
System.out.println("Null set");
 }

System.out.println();
return;
 }

subsequences.add(array[index]);
printSubsequences(index+1, array, size, subsequences); // pick
subsequences.remove(subsequences.size()-1);
printSubsequences(index+1, array, size, subsequences); // not pick
 }
publicstaticvoidmain(String[] args) {
Scannersc = newScanner(System.in);
System.out.println("Enter the number of test cases:");
intt = sc.nextInt();

while (t-- > 0){
System.out.println("Enter the size of the array:");
intsize = sc.nextInt();

int[] array = newint[size];
System.out.println("Enter the elements of the array:");
for(inti=0 ; i<size ; i++){
array[i] = sc.nextInt();
 }

ArrayList<Integer> subsequences = newArrayList<>();
printSubsequences(0, array, size, subsequences);
 }
 }
}