Algorithm to get permutations of two arrays in java [closed]

Question

Closed. This question needs details or clarity. It is not currently accepting answers.

Want to improve this question? As written, this question is lacking some of the information it needs to be answered. If the author adds details in comments, consider editing them into the question. Once there's sufficient detail to answer, vote to reopen the question.

Closed 4 years ago.

Improve this question

Hello StackOverflow community !

I need this :

List<String> s1 = Arrays.asList(new String[] {"A0","B0","C0","D0"});
List<String> s2 = Arrays.asList(new String[] {"E0","F0","G0","H0"});
int iteration = 3;

List<String> result = permutations(s1,s2,iteration);

//result should contain : "A0E0B0F0C0G0", "A0E0B0F0D0H0",...
//result should not contain : some String begining with E0 in this example
//result should not have duplicate values

//Expected behaviour : 
//Pick one of the strings from s1, pick one of the strings from s2.
//Concatenate both. Repeat this process "iteration" times.

I found this : Substituting a for-loop with all permutations of an array - Java

It's useful but I don't know how to change it for my code.

Any idea ?

Manohar Bhat · Accepted Answer · 2021-02-23 15:25:14Z

1

package stackoverflow;

import java.util.Arrays;
import java.util.List;

//Prints permutation of strings in 2 lists, first it takes string from first list and 
//then from second list, so on it repeats this process as the given "iteration" number of times
public class PermutationOfTwoArrays
{
    public static void main(String[] args)
    {
        int iteration=3;
        List<String> s1 = Arrays.asList(new String[] {"A0","B0","C0","D0"});
        List<String> s2 = Arrays.asList(new String[] {"E0","F0","G0","H0"});
        int[] indexes=new int[2*iteration];
        printPermutationOfTwoArrays(iteration,s1,s2,0,indexes);
    }

    private static void printPermutationOfTwoArrays(int iteration, List<String> s1,
            List<String> s2,int currentIteration,int[] indexes)
    {
        if(currentIteration>=3) {
            System.out.println(s1.get(indexes[0])+s2.get(indexes[1])+
                    s1.get(indexes[2])+s2.get(indexes[3])+
                    s1.get(indexes[4])+s2.get(indexes[5]));
            return;
        }
        for(int j=0;j<s1.size();j++) {
            indexes[2*currentIteration]=j;
            for(int k=0;k<s2.size();k++) {
                indexes[2*currentIteration+1]=k;
                printPermutationOfTwoArrays(iteration, s1, s2, currentIteration+1, indexes);
            }
        }
    }
}

answered Feb 23, 2021 at 15:25

Manohar Bhat

13610 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Benjamin Bettan Over a year ago

Thanks a lot, it seems perfect ! Well... as expected it's difficult to check the validity of your answer. I have some math to do to check it ;-)

Collectives™ on Stack Overflow

Algorithm to get permutations of two arrays in java [closed]

1 Answer 1

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Linked

Related