Permutation problem

JavaScript
1

hello, I am trying to solve no repeats algorithm, my code is

 function perMute(str){
   
    let resultArr = [] // in this array we will save our combinations
    str = str.split("");
  //let count how many combination is possible(factorial of length)
  let com = 1
  let len = str.length;
  for(let i =1;i<=len;i++){
      com*=i
  }
   // looping and swaping
  let places = len - 1;
  let start = 0;

  for(let i = 1;i<=com;i++){
      swapme(str,start,start+1);
      start++;
      if(start === len-1){
          start = 0;
      } // reset the start value if it's same as str length
  }
  
  // make a swap function

  function swapme(str,indexA,indexB){
      let tmp = str[indexA];
      str[indexA] = str[indexB];
      str[indexB] = tmp;
       // test the result and insert it
       let testing = /(.)\1+/;
       if(testing.test(resultArr[0])){
           resultArr.shift();
       }
       if(!testing.test(str.join(""))){
           resultArr.push(str.join(""));
       }
  }

  return resultArr.length

}

for perMute(“abc”),perMute(“aab”) the result is correct
however it didn’t return correct result in perMute(“abcdefa”)
please someone tell what i did wrong in this code

2

What is the link to this challenge, please?

3
4

Ok, brute force checking of all possibilities is possible but tricky. I think that your logic for generating all of the possible permutations is a bit off.

Can you describe to me, in words, how you should make every single permutation?

5

@JeremyLT thank you for your reply. I will try to describe it but sorry for my bad english

let’s take a string “abc”. this string has 6 combination.
I use n! formula to calculate number of combination.
n = length of string. “com” save the number of combination. the 6 combination is “abc”, “bac” , “bca”, “cba”, “cab” ,“acb”. every time the first letter it’s place. in “abc” first letter is “a” which change it’s position 2 times. abc > bac > bca. So, number of positon is string.length - 1. I save this value in place variable. I use swapMe function for swapping the position of letter. create a for loop. in every loop it will call the swapMe function.

6

Ok, 2 things

  1. I don’t see where you swap each string value to the start.
  2. I am not sure what you are doing with that test in the swap function.