Generate All Permutations of a String in Java: A Recursive Approach

Unleash the Power of Permutations in Java

When it comes to manipulating strings in Java, one of the most fascinating concepts is permutation. Essentially, permutation refers to the process of rearranging the characters of a string to form new strings. Take the string “ABC” for instance – its permutations include “ABC”, “ACB”, “BAC”, “BCA”, “CAB”, and “CBA”.

The Magic of Recursion

To generate all possible permutations of a string in Java, we can harness the power of recursion. This approach involves breaking down the problem into smaller sub-problems, solving each one, and then combining the results. By using recursion, we can efficiently compute all permutations of a given string.

Storing Permutations without Duplicates

To store the permutations, we utilize a set collection, which ensures that there are no duplicate permutations. This is particularly useful when dealing with large strings, as it prevents unnecessary repetition.

A Java Program to Get All Permutations

Here’s a sample Java program that demonstrates how to get all permutations of a string:
“`
import java.util.*;

public class Permutation {
public static void main(String[] args) {
String str = “ABC”;
permutation(str, 0, str.length()-1);
}

private static void permutation(String str, int l, int r) {
    if (l == r)
        System.out.println(str);
    else {
        for (int i = l; i <= r; i++) {
            str = swap(str,l,i);
            permutation(str, l+1, r);
            str = swap(str,l,i);
        }
    }
}

public static String swap(String a, int i, int j) {
    char temp;
    char[] charArray = a.toCharArray();
    temp = charArray[i];
    charArray[i] = charArray[j];
    charArray[j] = temp;
    return String.valueOf(charArray);
}

}
“`
Unlocking the Potential of Permutations

By mastering the art of permutation in Java, you can unlock a world of possibilities in string manipulation. Whether you’re working on a project that involves generating all possible combinations of a string or simply looking to improve your coding skills, understanding permutation is an essential tool to have in your arsenal.