mathball/lib/permutation/index.js

A JavaScript library for Competitive Programming

'use strict';

function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } else { return Array.from(arr); } }

/* String Permutation
 * Function: getAllPerm()
 */

var validate = require('../validation/string');

function getAllPerm(str) {
	var letters = str.split(''),
	    results = [[letters.shift()]];

	var _loop = function _loop() {
		var currLetter = letters.shift();
		var tmpResults = [];
		results.forEach(function (result) {
			var rIdx = 0;
			while (rIdx <= result.length) {
				var tmp = [].concat(_toConsumableArray(result));
				tmp.splice(rIdx, 0, currLetter);
				tmpResults.push(tmp);
				rIdx++;
			}
		});
		results = tmpResults;
	};

	while (letters.length) {
		_loop();
	}
	return results.map(function (letterArray) {
		return letterArray.join('');
	}).filter(function (el, idx, self) {
		return self.indexOf(el) === idx;
	}).sort();
}

exports.permutation = function (str) {
	validate(str, 'permutation');
	return getAllPerm(str);
};