permutations.js

permutations.js

/*
A function that generates every possible sequences of permutations
of elements in a given array. 

For example 
with a given array ['rock', 'paper', 'scissors']
and a size = 3; 
the output should look something like:
  [["rock", "rock", "rock"],
   ["rock", "rock", "paper"],
   ["rock", "rock", "scissors"],
   ["rock", "paper", "rock"],
    ...etc...
  ]
*/

var permutations = function (size, array) {
  var solutions = [];
  var solution = [];

  var findSolutions = function(n) {
    // base case
    if (n === size) {
      solutions.push(solution.slice());
      return;
    }
    
    for (var i = 0; i < array.length; i++) {
      solution.push(array[i]);
      findSolutions(n+1);
      solution.splice(n,1);
    }
  }
  findSolutions(0);
  return solutions;
};