An improved quicksort animation showing the active partition in black and the active pivot in red.
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July 30, 2017 21:01
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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?