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Last active Feb 17, 2018
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Quicksort V
license: gpl-3.0

A visualization of quicksort. Each row represents the state of the array after a single swap operation.

See also sortvis.org by Aldo Cortesi and sorting visualizations by Jason Davies.

(function() {
var radians = Math.PI / 180;
d3.scale.cubehelix = function() {
return d3.scale.linear()
.range([d3.hsl(300, .5, 0), d3.hsl(-240, .5, 1)])
.interpolate(d3.interpolateCubehelix);
};
d3.interpolateCubehelix = d3_interpolateCubehelix(1);
d3.interpolateCubehelix.gamma = d3_interpolateCubehelix;
function d3_interpolateCubehelix(γ) {
return function(a, b) {
a = d3.hsl(a);
b = d3.hsl(b);
var ah = (a.h + 120) * radians,
bh = (b.h + 120) * radians - ah,
as = a.s,
bs = b.s - as,
al = a.l,
bl = b.l - al;
if (isNaN(bs)) bs = 0, as = isNaN(as) ? b.s : as;
if (isNaN(bh)) bh = 0, ah = isNaN(ah) ? b.h : ah;
return function(t) {
var h = ah + bh * t,
l = Math.pow(al + bl * t, γ),
a = (as + bs * t) * l * (1 - l);
return "#"
+ hex(l + a * (-0.14861 * Math.cos(h) + 1.78277 * Math.sin(h)))
+ hex(l + a * (-0.29227 * Math.cos(h) - 0.90649 * Math.sin(h)))
+ hex(l + a * (+1.97294 * Math.cos(h)));
};
};
}
function hex(v) {
var s = (v = v <= 0 ? 0 : v >= 1 ? 255 : v * 255 | 0).toString(16);
return v < 0x10 ? "0" + s : s;
}
})();
<!DOCTYPE html>
<meta charset="utf-8">
<style>
body {
background: #000;
}
.line {
fill: none;
stroke: #000;
stroke-width: 6px;
stroke-linecap: round;
stroke-linejoin: round;
}
.line-halo {
stroke-linecap: butt;
stroke-width: 8px;
}
</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script src="cubehelix.js"></script>
<script>
var n = 100,
array = d3.shuffle(d3.range(n)),
swaps = quicksort(array.slice()),
elements = array.map(function(v, i) { return {value: v, indexes: [{time: 0, index: i}]}; });
var color = d3.scale.cubehelix()
.domain([0, n / 2, n - 1])
.range([d3.hsl(-40, 1, .4), d3.hsl(60, 1, 1), d3.hsl(160, 1, .4)]);
swaps.forEach(function(s, t) {
var i = s[0], j = s[1];
elements[i].indexes.push({time: t + 1, index: j});
elements[j].indexes.push({time: t + 1, index: i});
t = elements[i], elements[i] = elements[j], elements[j] = t;
});
elements.forEach(function(e) {
e.indexes.push({time: swaps.length + 1, index: e.indexes[e.indexes.length - 1].index});
});
var margin = {top: 20, right: 20, bottom: 20, left: 20},
rowHeight = 20,
strokeWidth = 6,
width = 960 - margin.left - margin.right,
height = (swaps.length + .5) * rowHeight;
var x = d3.scale.ordinal()
.domain(d3.range(n))
.rangePoints([0, width]);
var lineStraight = d3.svg.line()
.interpolate(interpolateLineStraight)
.x(function(d) { return x(d.index); })
.y(function(d) { return rowHeight * d.time; });
var lineSwap = d3.svg.line()
.interpolate(interpolateLineSwap)
.x(function(d) { return x(d.index); })
.y(function(d) { return rowHeight * d.time; });
var svg = d3.select("body").append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom)
.append("g")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
svg.append("g")
.attr("class", "line line--straight")
.selectAll("path")
.data(elements)
.enter().append("path")
.style("stroke", function(d) { return color(d.value); })
.attr("d", function(d) { return lineStraight(d.indexes); });
svg.append("g")
.attr("class", "line line--swap")
.selectAll("path")
.data(d3.merge(elements
.map(function(e) {
var swaps = d3.pairs(e.indexes).slice(0, -1);
swaps.forEach(function(s) { s.value = e.value; });
return swaps;
})))
.enter().append("path")
.style("stroke", function(d) { return color(d.value); })
.attr("d", function(d) { return lineSwap(d); })
.select(function() { return this.parentNode.insertBefore(this.cloneNode(false), this); })
.attr("class", "line-halo")
.style("stroke", null)
.style("stroke-dasharray", function() {
var l = this.getTotalLength();
return "0," + strokeWidth / 2 + "," + (l - strokeWidth) + "," + strokeWidth / 2;
});
function interpolateLineStraight(points) {
var p0 = points[0],
x0 = p0[0],
y0 = p0[1],
path = [p0];
for (var i = 1, n = points.length, p1, x1, y1; i < n; ++i) {
p1 = points[i];
x1 = p1[0];
y1 = p1[1];
path.push("V", y1 - rowHeight / 2, "M", p1);
x0 = x1;
y0 = y1;
}
return path.join("");
}
function interpolateLineSwap(points) {
var p0 = points[0],
x0 = p0[0],
y0 = p0[1],
path = [p0];
for (var i = 1, n = points.length, p1, x1, y1; i < n; ++i) {
p1 = points[i];
x1 = p1[0];
y1 = p1[1];
path.push("M", x0, ",", y1 - rowHeight / 2, "L", p1);
x0 = x1;
y0 = y1;
}
return path.join("");
}
function quicksort(array) {
var swaps = [];
function partition(left, right, pivot) {
var v = array[pivot];
swap(pivot, --right);
for (var i = left; i < right; ++i) if (array[i] <= v) swap(i, left++);
swap(left, right);
return left;
}
function swap(i, j) {
if (i === j) return;
var t = array[i];
array[i] = array[j];
array[j] = t;
swaps.push([i, j]);
}
function recurse(left, right) {
if (left < right - 1) {
var pivot = partition(left, right, (left + right) >> 1);
recurse(left, pivot);
recurse(pivot + 1, right);
}
}
recurse(0, array.length);
return swaps;
}
d3.select(self.frameElement).style("height", height + margin.top + margin.bottom + "px");
</script>
@rhgrafix

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@rhgrafix rhgrafix commented Feb 17, 2018

Excellent code!

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