82 lines
2.0 KiB
JavaScript
82 lines
2.0 KiB
JavaScript
import { flatten } from '../../utils/array.js';
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import { factory } from '../../utils/factory.js';
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var name = 'setPowerset';
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var dependencies = ['typed', 'size', 'subset', 'compareNatural', 'Index'];
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export var createSetPowerset = /* #__PURE__ */factory(name, dependencies, _ref => {
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var {
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typed,
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size,
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subset,
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compareNatural,
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Index
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} = _ref;
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/**
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* Create the powerset of a (multi)set. (The powerset contains very possible subsets of a (multi)set.)
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* A multi-dimension array will be converted to a single-dimension array before the operation.
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*
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* Syntax:
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*
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* math.setPowerset(set)
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*
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* Examples:
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*
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* math.setPowerset([1, 2, 3]) // returns [[], [1], [2], [3], [1, 2], [1, 3], [2, 3], [1, 2, 3]]
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*
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* See also:
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*
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* setCartesian
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*
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* @param {Array | Matrix} a A (multi)set
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* @return {Array} The powerset of the (multi)set
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*/
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return typed(name, {
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'Array | Matrix': function ArrayMatrix(a) {
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if (subset(size(a), new Index(0)) === 0) {
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// if empty, return empty
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return [];
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}
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var b = flatten(Array.isArray(a) ? a : a.toArray()).sort(compareNatural);
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var result = [];
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var number = 0;
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while (number.toString(2).length <= b.length) {
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result.push(_subset(b, number.toString(2).split('').reverse()));
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number++;
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} // can not return a matrix, because of the different size of the subarrays
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return _sort(result);
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}
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}); // create subset
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function _subset(array, bitarray) {
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var result = [];
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for (var i = 0; i < bitarray.length; i++) {
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if (bitarray[i] === '1') {
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result.push(array[i]);
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}
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}
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return result;
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} // sort subsests by length
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function _sort(array) {
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var temp = [];
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for (var i = array.length - 1; i > 0; i--) {
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for (var j = 0; j < i; j++) {
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if (array[j].length > array[j + 1].length) {
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temp = array[j];
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array[j] = array[j + 1];
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array[j + 1] = temp;
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}
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}
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}
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return array;
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}
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}); |