You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
99 lines
2.8 KiB
JavaScript
99 lines
2.8 KiB
JavaScript
(function (exports) {
|
|
|
|
'use strict';
|
|
|
|
function compare(a, b) {
|
|
return a - b;
|
|
}
|
|
|
|
/**
|
|
* Quicksort algorithm
|
|
*
|
|
* @public
|
|
* @param {array} array Array which should be sorted.
|
|
* @return {array} Sorted array.
|
|
*/
|
|
var quickSort = (function () {
|
|
|
|
/**
|
|
* Partitions the array in two parts by the middle elements.
|
|
* All elemnts which are less than the chosen one goes left from it
|
|
* all which are greater goes right from it.
|
|
* Uses Hoare's partitioning algorithm.
|
|
*
|
|
* @param {array} array Array which should be partitioned
|
|
* @param {number} left Left part of the array
|
|
* @param {number} right Right part of the array
|
|
* @return {number}
|
|
*/
|
|
function partition(array, left, right, cmp) {
|
|
var pivot = array[Math.floor((left + right) / 2)];
|
|
var temp;
|
|
while (left <= right) {
|
|
while (cmp(array[left], pivot) < 0) {
|
|
left += 1;
|
|
}
|
|
while (cmp(array[right], pivot) > 0) {
|
|
right -= 1;
|
|
}
|
|
if (left <= right) {
|
|
temp = array[left];
|
|
array[left] = array[right];
|
|
array[right] = temp;
|
|
left += 1;
|
|
right -= 1;
|
|
}
|
|
}
|
|
return left;
|
|
}
|
|
|
|
/**
|
|
* Recursively calls itself with different values for
|
|
* left/right part of the array which should be processed
|
|
*
|
|
* @private
|
|
* @param {array} array Array which should be processed
|
|
* @param {number} left Left part of the array which should be processed
|
|
* @param {number} right Right part of the array which should be processed
|
|
*/
|
|
function quicksort(array, left, right, cmp) {
|
|
var mid = partition(array, left, right, cmp);
|
|
if (left < mid - 1) {
|
|
quicksort(array, left, mid - 1, cmp);
|
|
}
|
|
if (right > mid) {
|
|
quicksort(array, mid, right, cmp);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Quicksort algorithm. In this version of quicksort used
|
|
* middle element of array for the pivot.<br><br>
|
|
* Time complexity: O(N log(N)).
|
|
*
|
|
* @example
|
|
*
|
|
* var sort = require('path-to-algorithms/src' +
|
|
* '/sorting/quicksort-middle').quickSort;
|
|
* console.log(sort([2, 5, 1, 0, 4])); // [ 0, 1, 2, 4, 5 ]
|
|
*
|
|
* @public
|
|
* @module sorting/quicksort-middle
|
|
* @param {Array} array Input array.
|
|
* @param {Function} cmp Optional. A function that defines an
|
|
* alternative sort order. The function should return a negative,
|
|
* zero, or positive value, depending on the arguments.
|
|
* @return {Array} Sorted array.
|
|
*/
|
|
return function (array, cmp) {
|
|
cmp = cmp || compare;
|
|
quicksort(array, 0, array.length - 1, cmp);
|
|
return array;
|
|
};
|
|
|
|
}());
|
|
|
|
exports.quickSort = quickSort;
|
|
|
|
})(typeof window === 'undefined' ? module.exports : window);
|