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April 13, 2018 16:26
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A Variety-Sort in ES6
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function varietySort(array) { | |
// 1. Cut the list in half | |
const [ left, right ] = varietySort.split(array); | |
varietySort.rejoin( | |
array, | |
varietySort.left(left), | |
varietySort.right(right) | |
); | |
return array; | |
} | |
varietySort.split = function(array) { | |
const left = array.splice(0, array.length / 2); | |
const right = array.splice(0); | |
return [ left, right ]; | |
} | |
varietySort.rejoin = function(array, left, right) { | |
while(left.length && right.length) { | |
if (left[0] < right[0]) { | |
array.push(left.shift()); | |
} else if (right[0] < left[0]) { | |
array.push(right.shift()); | |
} | |
} | |
if (left.length) { | |
[].push.apply(array, left); | |
} | |
if (right.length) { | |
[].push.apply(array, right); | |
} | |
return array; | |
} | |
// Bubble-sort until the right-half of this array is sorted | |
varietySort.left = function(array) { | |
for (let j = array.length; j > (array.length / 2) + 1; --j) { | |
for (let i = 1; i < array.length; ++i) { | |
if (array[i] < array[i - 1]) { | |
[ array[i], array[i - 1] ] = [ array[i - 1], array[i] ]; | |
} | |
} | |
} | |
const [ left, right ] = varietySort.split(array); | |
return varietySort.rejoin( | |
array, | |
varietySort.left.left(left), | |
varietySort.left.right(right), | |
); | |
}; | |
varietySort.left.left = function(array) { | |
const from = array.splice(0, array.length); | |
for (let i = 0; i < from.length; ++i) { | |
let j = 0; | |
while (j < array.length && from[i] > array[j]) { | |
j++; | |
} | |
array.splice(j, 0, from[i]); | |
} | |
return array; | |
} | |
varietySort.left.right = function(array) { | |
return array; | |
} | |
// Cut this half in half | |
varietySort.right = function(array) { | |
const [ left, right ] = varietySort.split(array); | |
return varietySort.rejoin( | |
array, | |
varietySort.right.left(left), | |
varietySort.right.right(right), | |
); | |
} | |
varietySort.right.left = function(array) { | |
const shuffle = () => { | |
for (let i = array.length - 1; i > 0; --i) { | |
const j = Math.floor(Math.random() * (i + 1)); | |
[ array[i], array[j] ] = [ array[j], array[i] ]; | |
} | |
}; | |
for (let i = 1; i < array.length; ++i) { | |
if (array[i] < array[i - 1]) { | |
i = 0; | |
shuffle(); | |
} | |
} | |
return array; | |
} | |
varietySort.right.right = function quickSort(array, low = 0, high = array.length - 1) { | |
const partition = (low, high) => { | |
let pivot = array[high]; | |
let i = low - 1; | |
for (let j = low; j <= high - 1; ++j) { | |
if (array[j] <= pivot) { | |
++i; | |
[ array[j], array[i] ] = [ array[i], array[j] ]; | |
} | |
} | |
[ array[i + 1], array[high] ] = [ array[high], array[i + 1] ]; | |
return i + 1; | |
}; | |
if (low < high) { | |
const pi = partition(low, high); | |
quickSort(array, low, pi - 1); | |
quickSort(array, pi, high); | |
} | |
return array; | |
} | |
const array = [1, 10, 12, 3, 8, 11, 4, 9, 13, 16, 6, 2, 7, 15, 14, 5]; | |
console.log(array); | |
console.log(varietySort(array)); |
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