An improved quicksort animation showing the active partition in black and the active pivot in red.
Last active
May 13, 2024 17:31
Quicksort IV
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| license: gpl-3.0 |
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| <!DOCTYPE html> | |
| <meta charset="utf-8"> | |
| <style> | |
| .line { | |
| stroke: #000; | |
| stroke-width: 1.5px; | |
| stroke-linecap: round; | |
| } | |
| .line--pivot { | |
| stroke: #f00; | |
| stroke-width: 2.5px; | |
| } | |
| .line--inactive { | |
| stroke: #ddd; | |
| stroke-width: 1px; | |
| } | |
| </style> | |
| <body> | |
| <script src="//d3js.org/d3.v3.min.js"></script> | |
| <script> | |
| var n = 200, | |
| array = d3.shuffle(d3.range(n)), | |
| actions = quicksort(array.slice()).reverse(); | |
| var margin = {top: 230, right: 40, bottom: 230, left: 40}, | |
| width = 960 - margin.left - margin.right, | |
| height = 500 - margin.top - margin.bottom; | |
| var x = d3.scale.ordinal() | |
| .domain(d3.range(n)) | |
| .rangePoints([0, width]); | |
| var a = d3.scale.linear() | |
| .domain([0, n - 1]) | |
| .range([-45, 45]); | |
| 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 + ")"); | |
| var line = svg.append("g") | |
| .attr("class", "line") | |
| .selectAll("line") | |
| .data(array) | |
| .enter().append("line") | |
| .attr("transform", transform) | |
| .attr("y2", -height); | |
| var transition = d3.transition() | |
| .duration(150) | |
| .each("start", function start() { | |
| var action = actions.pop(); | |
| switch (action.type) { | |
| case "swap": { | |
| var i = action[0], | |
| j = action[1], | |
| li = line[0][i], | |
| lj = line[0][j]; | |
| line[0][i] = lj; | |
| line[0][j] = li; | |
| transition.each(function() { line.transition().attr("transform", transform); }); | |
| break; | |
| } | |
| case "partition": { | |
| line.attr("class", function(d, i) { | |
| return i === action.pivot ? "line--pivot" | |
| : action.left <= i && i < action.right ? null | |
| : "line--inactive"; | |
| }); | |
| break; | |
| } | |
| } | |
| if (actions.length) transition = transition.transition().each("start", start); | |
| else transition.each("end", function() { line.attr("class", null); }); | |
| }); | |
| function transform(d, i) { | |
| return "translate(" + x(i) + "," + height + ")rotate(" + a(d) + ")"; | |
| } | |
| function quicksort(array) { | |
| var actions = []; | |
| 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; | |
| actions.push({type: "swap", "0": i, "1": j}); | |
| } | |
| function recurse(left, right) { | |
| if (left < right - 1) { | |
| var pivot = (left + right) >> 1; | |
| actions.push({type: "partition", "left": left, "pivot": pivot, "right": right}); | |
| pivot = partition(left, right, pivot); | |
| recurse(left, pivot); | |
| recurse(pivot + 1, right); | |
| } | |
| } | |
| recurse(0, array.length); | |
| return actions; | |
| } | |
| </script> |
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Hey Mike,
I was trying to convert this to the d3 v4 API but am having some trouble. Specifically, I'm not sure how to update lines 62-67:
Do you have any tips?