d3-sort-visualization/js/quicksort.js

/**
 *
 */
var QuickSort = function(VisualizerInstance) {
    this.swaps = 0;
    this.comparisons = 0;
    this.V = VisualizerInstance;

    this.V
        .instruct(this.V.hideMarker, 0, 1)
        .instruct(this.V.hideMarker, 0, 2)
        .instruct(this.V.message, 0, 2, 'Swaps: ' + this.swaps)
        .instruct(this.V.message, 0, 1, 'Comparisons: ' + this.comparisons);
};

QuickSort.prototype = Object.create(Sorter.prototype);

// NOTE adds to an instruction set
/**
 *
 */
QuickSort.prototype.sort = function(arr, start, end) {
    if (end <= start) {
        // message: Left and Right have crossed, start sorting sublists.
        return arr;
    }

    var left = start;
    var right = end;

    var pivot = Math.floor((right + left) / 2);
    var pivotval = arr[pivot].value;
    var tmp;
    var rval;

    this.V
        .instruct(this.V.marker, 0, 1, left, 'L')
        .instruct(this.V.marker, 0, 2, right, 'R')

        .instruct(this.V.showMarker, 0, 1)
        .instruct(this.V.showMarker, 0, 2)

        .instruct(this.V.unhighlight, 0)
        .instruct(this.V.highlight, 0, pivot)

        .instruct(this.V.fade, 0, -1, start - 1)
        .instruct(this.V.fade, 0, end + 1, arr.length)
        // Message: pivot chosen

        .instruct(this.V.message, 0, 3, 'Sorting from [' + start + '] to [' + end + ']')
        .instruct(this.V.message, 0, 4, '')
        .instruct(this.V.message, 100, 5, '');

    while (left <= right) {

        this.V.instruct(this.V.message, 0, 4, '');
        this.V.instruct(this.V.message, 0, 5, '');

        while (arr[left].value < pivotval) {
            this.comparisons++;
            this.V
                .instruct(this.V.message, 0, 4, `${arr[left].value} < ${pivotval}, increment left` )
                .instruct(this.V.message, 0, 1, `Comparisons: ${this.comparisons}`)
                .instruct(this.V.marker, 500, 1, left);

            left++;
        }

        this.V
            .instruct(this.V.message, 0, 4, `Left stop: ${arr[left].value} >= ${pivotval}`)
            .instruct(this.V.marker, 500, 1, left);

        while (arr[right].value > pivotval) {
            this.comparisons++;
            this.V
                .instruct(this.V.message, 0, 5, `${arr[right].value} > ${pivotval}, decrement right`)
                .instruct(this.V.message, 0, 1, 'Comparisons: ' + this.comparisons)
                .instruct(this.V.marker, 100, 2, right);

            right--;
        }

        this.V
            .instruct(this.V.message, 0, 5, `Right stop: ${arr[right].value} <= ${pivotval} `)
            .instruct(this.V.marker, 100, 2, right);

        if (left <= right) {
            tmp = arr[left];
            arr[left] = arr[right];
            arr[right] = tmp;

           this.V.instruct(this.V.swap, 100, left, right);

            left++;
            right--;

            this.swaps++;

            this.V
                .instruct(this.V.message, 0, 2, 'Swaps: ' + this.swaps)
                .instruct(this.V.message, 0, 4, 'Incremement left...')
                .instruct(this.V.message, 0, 5, 'Decrement right...')
                .instruct(this.V.marker, 100, 1, left)
                .instruct(this.V.marker, 100, 2, right)

        }
    }

    this.V
        .instruct(this.V.unfade, 0)
        .instruct(this.V.unhighlight, 0)
        .instruct(this.V.hideMarker, 0, 1)
        .instruct(this.V.hideMarker, 0, 2)
        .instruct(this.V.message, 0, 3, 'Sorting complete.')
        .instruct(this.V.message, 0, 4, '')
        .instruct(this.V.message, 0, 5, '');

    this.sort(arr, start, right);
    this.sort(arr, left, end);

    return arr;
};