Question

Write a java code to solve the following question using the backtracking algorithm.

Given a set of distinct integers, return all possible subsets.

input: new int[] {1,2,3}

output: [], [3], [2], [2,3], [1], [1,3], [1,2], [1,2,3]

What to submit: 1. Your source code in a text document (15pts), 2. A screen copy showing you can run the code and the result of running the code (5 pts). 3. What is the performance of your algorithm (5 pts), give the answer, and very brief discussion.

Answer 1

Please refer to the following code below:-

import java.util.ArrayList;
import java.util.List;
public class Backtracking {
    // main function to start the program
    public static void main(String[] args) {
        // Creating object for backtracking
        Backtracking b= new Backtracking();
        // Declaring array
        int[] a= {1, 2, 3};
        // creating list of lists
        List<List<Integer>> sub = b.sub(a);
        // printing all subsets
        System.out.println(sub);
    }
    // sub function
    public List<List<Integer>> sub(int[] a) {
        List<List<Integer>> list = new ArrayList<>();
        // calling function to store elements of array
        subsets(list, new ArrayList<>(), a, 0);
        return list;
    }
    // this method will create subset
    private void subsets(List<List<Integer>> list , List<Integer> result, int [] a, int begin){
        list.add(new ArrayList<>(result));
        // iterating in array
        for(int i = begin; i < a.length; i++){
            // add element
            result.add(a[i]);
            // Explore
            subsets(list, result, a, i + 1);
            // remove
            result.remove(result.size() - 1);
        }
    }

}

Output:-

[[], [1], [1, 2], [1, 2, 3], [1, 3], [2], [2, 3], [3]]

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Please Refer to the following images:-

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Time complexity:- O(2ⁿ)

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Please upvote

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