quicksort javascript
var items = [5,3,7,6,2,9];
function swap(items, leftIndex, rightIndex){
var temp = items[leftIndex];
items[leftIndex] = items[rightIndex];
items[rightIndex] = temp;
}
function partition(items, left, right) {
var pivot = items[Math.floor((right + left) / 2)], //middle element
i = left, //left pointer
j = right; //right pointer
while (i <= j) {
while (items[i] < pivot) {
i++;
}
while (items[j] > pivot) {
j--;
}
if (i <= j) {
swap(items, i, j); //sawpping two elements
i++;
j--;
}
}
return i;
}
function quickSort(items, left, right) {
var index;
if (items.length > 1) {
index = partition(items, left, right); //index returned from partition
if (left < index - 1) { //more elements on the left side of the pivot
quickSort(items, left, index - 1);
}
if (index < right) { //more elements on the right side of the pivot
quickSort(items, index, right);
}
}
return items;
}
// first call to quick sort
var sortedArray = quickSort(items, 0, items.length - 1);
console.log(sortedArray); //prints [2,3,5,6,7,9]