quicksort.js

var quicksort = function(A) {

	var swap = function(a, b) {
		var temp = A[a];
		A[a] = A[b];
		A[b] = temp;
	}

	var partition = function(left, right) {
		var pivotIndex = Math.floor((left + right) / 2);
		var pivotValue = A[pivotIndex];

		swap(pivotIndex, right);

		var storeIndex = left;

		for (var i = left; i < right; i++) {
			if (A[i] <= pivotValue) {
				swap(i, storeIndex);
				storeIndex = storeIndex + 1;
			}
		};

		swap(storeIndex, right);

		return storeIndex;
	}

	var sort = function(i, k) {
		if (i < k) {
			var p = partition(i, k);
			sort(i, p - 1);
			sort(p + 1, k);
		}
	}

	sort(0, A.length - 1);

	return A;
}