# Recognizing a Pattern in My Recursive Functions

Shawn Drost from Hack Reactor taught me to write recursive functions with an if-else statement:

``function recursion() {  if(baseCase) {    // do something  } else {    // get me 1 step closer to the base case  }}``

As I was reviewing some of my curriculum material from Hack Reactor and thrashing about at codewars, I started to recognize a common pattern in my code when dealing with permutation problems that built on top of Shawn’s suggestion.

Here’s some code I would write if I had to find all the different permutations of a string called `problem`.

``function findAllAnswers(problem) {  var partialAnswer = "";  var allAnswers = [];  findAnswers(problem);  return allAnswers;  function findAnswer(problem) {    if(problem.length === 0) {      allAnswers.push(partialAnswer);      return;    }    else {      // add the first bit of 'problem' to partialAnswer      partialAnswer.push(problem[0]);      // explore all branches that include this first bit      findAnswer(problem.slice(1));      // lets remove what we added just before the recursive call      partialAnswer = partialAnswer.substring(0, partialAnswer.length - 1);    }  }}``

I used this approach to solve the N-Queens problem, list all possibilities of a rock-paper-scissors matchup, and find all permutations of words you could be typing into a T-9 cell phone numpad.

The key components that jump out to me are:

1. I only have one `partialAnswers` variable that I manipulate until it meets the criteria for being a complete answer. Then I push the single solution to my `allAnswers` array.
2. I explore all branches of the first possibility, then backtrack one step at a time until I return to my original state. At that point, I start exploring all branches for the next possibility.
3. My code ends up being mostly simple and clean. I only need to worry about one parameter/argument in this simple problem. (My previous, unrefined approach would have required two arguments: `remainingProblem` and `answerSoFar`, which can be a bit of a mess to keep in order.)

The sorcery that happens in the `else` statement is something I may have previously struggled to come up with, but now it feels like child's play. (That's good, right?)

Next up? Maybe tail recursion.