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.
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February 17, 2018 18:34
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Quicksort V
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| license: gpl-3.0 |
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| (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; | |
| } | |
| })(); |
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| <!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> |
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Excellent code!