การจัดเรียง (Sort)

<script>
var a = [4, 1, 3, 5, 2, 6]; 
function bubbleSort(a)
{
    var swapped;
    do {
        swapped = false;
        for (var i=0; i < a.length-1; i++) {
            if (a[i] > a[i+1]) {
                var temp = a[i];
                a[i] = a[i+1];
                a[i+1] = temp;
                swapped = true;
            }
        }
    } while (swapped);
}
console.log(a); 
bubbleSort(a);
console.log(a);
</script>

<script>
var a = [4, 1, 3, 5, 2, 6]; 
function selectionSort(a) {  
    var length = a.length;
    for (var i = 0; i < length - 1; i++) {
        var min = i;
        for (var j = i + 1; j < length; j++) { 
            if (a[j] < a[min]) { 
                min = j; 
            }
        }
        if (min != i) {
            var tmp = a[i];
            a[i] = a[min];
            a[min] = tmp;
        }
    }
}
console.log(a);
selectionSort(a);
console.log(a);
</script>

<script>
var a = [4, 1, 3, 5, 2, 6]; 
console.log(a);
quickSort(a, 0, a.length -1);
console.log(a);
function  quickSort(arr, left, right)
{
	var i = left;
	var j = right;
	var tmp;
	pivotidx = (left + right) / 2; 
	var pivot = parseInt(arr[pivotidx.toFixed()]);  
	/* partition */
	while (i <= j)
	{
		while (parseInt(arr[i]) < pivot) 	i++;
		while (parseInt(arr[j]) > pivot) 	j--;
		if (i <= j)
		{
			tmp = arr[i];
			arr[i] = arr[j];
			arr[j] = tmp;
			i++;
			j--;
		}
	}
	/* recursion */
	if (left < j) quickSort(arr, left, j);
	if (i < right) quickSort(arr, i, right);
	return arr;
}
</script>

<script>
var a = [4, 1, 3, 5, 2, 6]; 
console.log(a);
heapSort(a);
console.log(a);

function swap(a, i, j) {
    var tmp = a[i];
    a[i] = a[j];
    a[j] = tmp;
}

function max_heapify(a, i, length) {
    while (true) {
        var left = i*2 + 1;
        var right = i*2 + 2;
        var largest = i;

        if (left < length && a[left] > a[largest]) {
            largest = left;
        }

        if (right < length && a[right] > a[largest]) {
            largest = right;
        }

        if (i == largest) {
            break;
        }

        swap(a, i, largest);
        i = largest;
    }
}

function heapify(a, length) {
    for (var i = Math.floor(length/2); i >= 0; i--) {
        max_heapify(a, i, length);
    }
}

function heapSort(a) {
    heapify(a, a.length);
    for (var i = a.length - 1; i > 0; i--) {
        swap(a, i, 0);
        max_heapify(a, 0, i-1);
    }
}
</script>