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(function (exports) {
'use strict';
var permutations = (function () {
var res;
function swap(arr, i, j) {
var temp = arr[i];
arr[i] = arr[j];
arr[j] = temp;
}
function permutations(arr, current) {
if (current >= arr.length) {
return res.push(arr.slice());
}
for (var i = current; i < arr.length; i += 1) {
swap(arr, i, current);
permutations(arr, current + 1);
swap(arr, i, current);
}
}
/**
* Finds all the permutations of given array.<br><br>
* Permutation relates to the act of rearranging, or permuting,
* all the members of a set into some sequence or order.
* For example there are six permutations of the set {1,2,3}, namely:
* (1,2,3), (1,3,2), (2,1,3), (2,3,1), (3,1,2), and (3,2,1).<br><br>
* Complexity: O(N*N!).
*
* @example
*
* var permutations = require('path-to-algorithms/src/' +
* 'combinatorics/permutations').permutations;
* var result = permutations(['apple', 'orange', 'pear']);
*
* // [ [ 'apple', 'orange', 'pear' ],
* // [ 'apple', 'pear', 'orange' ],
* // [ 'orange', 'apple', 'pear' ],
* // [ 'orange', 'pear', 'apple' ],
* // [ 'pear', 'orange', 'apple' ],
* // [ 'pear', 'apple', 'orange' ] ]
* console.log(result);
*
* @module combinatorics/permutations
* @public
* @param {Array} arr Array to find the permutations of.
* @returns {Array} Array containing all the permutations.
*/
return function (arr) {
res = [];
permutations(arr, 0);
var temp = res;
// Free the extra memory
res = null;
return temp;
};
}());
exports.permutations = permutations;
}((typeof window === 'undefined') ? module.exports : window));