String Permutations

string-permutations.go

package main

import "fmt"

func main() {
	permutations := createPermutations("abc")
	fmt.Println(permutations)
}

func createPermutations(s string) (permutations []string) {
	if len(s) < 2 {
		return []string{s}
	}

	for i, r := range s {
		remainder := s[0:i] + s[i+1:]
		for _, chars := range createPermutations(remainder) {
			permutations = append(permutations, string(r)+chars)
		}
	}

	return
}

string-permutations.java

// I don't know Java, show me a better way.
import java.util.ArrayList;

class Sandbox {
    public static void main(String[] args) {
        ArrayList<String> permutations = createPermutations("abc");
        System.out.println(permutations.toString());
    }

    private static ArrayList<String> createPermutations(String str) {
        ArrayList<String> permutations = new ArrayList<String>();
        if (str.length() < 2) {
            permutations.add(str);
            return permutations;
        }

        char[] characters = str.toCharArray();

        for (int i = 0; i < characters.length; i++) {
            char ch = characters[i];
            StringBuilder remainder = new StringBuilder();
            for (int j = 0; j < characters.length; j++) {
                if (i != j) {
                    remainder.append(characters[j]);
                }
            }
            for (String chars : createPermutations(remainder.toString())) {
                permutations.add(ch + chars);
            }
        }

        return permutations;
    }
}

string-permutations.js

#!/usr/bin/env node
function createPermutations(str) {
    if (str.length < 2) {
      return [str];
    }
  
    const permutations = [];
  
    for (let i = 0, len = str.length; i < len; i++) {
      let char = str.charAt(i);
      let remaining = str.slice(0, i) + str.slice(i + 1, len);
  
      for (const permutation of createPermutations(remaining)) {
        permutations.push(char + permutation);
      }
    }
    return permutations;
  }
  
  const permutations = createPermutations("abc");
  console.log(permutations);
  

string-permutations.rb

#!/usr/bin/env ruby
# I don't know Ruby, show me a better way.

def create_permuations(s)
    return [s] if s.length < 2

    permutations = []

    s.split("").each_with_index do |ch, i|
        remainder = s[0...i] + s[i+1..-1]
        create_permuations(remainder).each do |s|
            permutations.append(ch + s)
        end
    end

   return permutations 
end


if __FILE__ == $0
    output = create_permuations("abc")
    puts output
end

string_permutations.py

#!/usr/bin/env python3
from typing import List


def create_permutations(string: str) -> List[str]:
    if len(string) < 2:
        return [string]

    perumations = []

    for i, c in enumerate(string):
        remainder = string[0:i] + string[i+1:]
        for chars in create_permutations(remainder):
            perumations.append(c + chars)

    return perumations


if __name__ == "__main__":
    permutation = create_permutations("abc")
    print(permutation)